Diplomacy

The restored Bulgarian state entered international politics with an ambitious ideological program. Its rulers sought not merely territorial independence from Byzantium but recognition of a sovereign Bulgarian monarchy and church. The title associated especially with Kaloyan, ruler of Bulgaria and Vlachia, reflected authority over Moesia, parts of Thrace and Macedonia, and territories north of the Danube then known as Vlachia. Yet the new monarchy had inherited neither uncontested legitimacy nor secure frontiers. Its diplomacy therefore combined claims drawn from the earlier Bulgarian imperial tradition with pragmatic appeals to powers outside the Orthodox Byzantine order.

Kaloyan’s relations with the papacy were the clearest expression of this search for recognition. He doubted whether a crown bestowed by the archbishop of Tarnovo alone possessed sufficient international legitimacy and consequently turned to Rome. Papal recognition and the royal crown received in 1204 strengthened his standing at the moment when the Fourth Crusade destroyed Byzantine rule in Constantinople and created the Latin Empire. Kaloyan could now present himself as a ruler recognized beyond the Balkans while exploiting the political vacuum left by the Byzantine collapse. His conquests in Macedonia and Thrace were accompanied by ecclesiastical measures: Greek bishops considered unreliable were removed and replaced by Slavic clergy, while suspect inhabitants were transferred to the Danubian lands. Thus diplomacy, conquest and church policy worked together to consolidate Bulgarian sovereignty.

Relations with the Latin Empire nevertheless showed that recognition did not create permanent alignment. Bulgaria and the crusader regime became rivals over the Byzantine inheritance, and Kaloyan’s successors had to maneuver among the Latins, Hungary and the Greek successor states. Under Boril, weakened by internal rivals and separatist principalities, Bulgaria entered close relations with Hungary around 1213 and received Hungarian help against a rebellion at Vidin. Boril also maintained an alliance with the Latin emperor Henry, while a projected engagement in 1214 between Boril’s daughter and the future Béla IV was intended to reinforce the Hungarian connection. These arrangements restricted the freedom of separatists such as Alexios Slav, who responded by moving toward Epiros and sealing his new association through marriage in 1216. Dynastic marriage had already become one of the principal instruments by which Bulgarian rulers and regional lords changed diplomatic camps.

Ivan Asen II’s accession in 1218 transformed Bulgaria’s position. When the returning Hungarian king Andrew II reached the Bulgarian frontier late that year, Ivan Asen detained him and permitted him to continue only after he accepted a marriage between the Bulgarian ruler and his daughter Maria. The wedding took place early in 1221. The marriage was not simply a family compact: Beograd and Branichevo, disputed Danubian strongholds, apparently passed to Ivan Asen as Maria’s dowry. In this way dynastic diplomacy achieved what war might have made costly, temporarily restoring Bulgarian authority in a region contested with Hungary throughout the thirteenth century.

Ivan Asen II initially observed the rivalry among the Latin Empire, Epiros, Nicaea and the Bulgarian state from a strategically advantageous position. Epiros had become the most vigorous Balkan power under Theodore, but its defeat by Ivan Asen in 1230 destroyed its imperial predominance. Bulgarian power then extended into Greek, Albanian and Serbian lands, while another dynastic bond linked Ivan Asen’s family to the Serbian ruler Stefan Vladislav. The victory did more than enlarge Bulgaria: it altered the balance among the successor states competing for Constantinople and enabled Tarnovo to aspire to leadership in the Orthodox world. The older formula including Vlachia receded as the monarchy’s political ideology turned more directly toward Bulgarian hegemony among Orthodox states.

Commercial diplomacy complemented this expansion. In 1230 Ivan Asen II granted Dubrovnik a charter permitting Ragusan merchants to trade freely in Bulgarian cities, including Beograd and Branichevo. The charter demonstrated both the geographical reach of Bulgarian claims and the crown’s willingness to use privileges for foreign merchants to stimulate exchange and bind distant urban communities to the monarchy. Access to Adriatic traders widened Bulgaria’s diplomatic horizon beyond its immediate land frontiers. Commercial agreements were not separate from high politics: they advertised control of contested provinces, encouraged customs revenue and offered foreign communities an interest in the stability of Bulgarian rule.

The struggle for Constantinople soon forced Ivan Asen to reassess his partners. After John of Brienne assumed power in the Latin capital in 1231, Bulgaria opened negotiations with Nicaea and in 1232 aligned with it against the Latin Empire. Hungary, a Catholic protector of the Latin regime, reacted by taking Beograd and Branichevo and besieging Vidin in 1232; although a Bulgarian relief army was defeated, Vidin itself held out. In 1234 Ivan Asen’s daughter was betrothed to the Nicaean heir, and in 1235 the Bulgarian and Nicaean courts met at Gallipoli. The settlement included important ecclesiastical concessions: Tarnovo abandoned jurisdictional claims over Thessaloniki, Mount Athos and eastern Thrace, and recognized the Nicaean patriarch as ecumenical patriarch. The marriage alliance and church agreement made possible joint operations against Constantinople.

Yet Ivan Asen’s diplomacy remained flexible rather than doctrinaire. During the siege of Constantinople in 1235–1236, he recognized that a Nicaean victory would restore a powerful Greek empire in the city and might be more dangerous to Bulgaria than the weak Latin regime. He therefore broke the alliance, sought the return of his daughter and recruited Cuman forces against Nicaea. By the end of his reign he again improved relations with Hungary and, indirectly, with the Latin Empire. The emergence of the Tatars supplied a compelling reason: the destruction of the Cuman state in 1238–1239 and the conquest of Kiev in 1240 placed a formidable steppe power on the borders of both Bulgaria and Hungary. A Bulgarian envoy was well received by King Béla in the first months of 1240, indicating movement toward common defense against a danger greater than their Danubian disputes.

After Ivan Asen’s death, the diplomatic system became harder to control. Minority rulers, quarrelling regents and provincial boyars weakened the personal bonds that had held the realm together, while the Mongol-Tatar invasions of 1241–1242 removed the friendly Cuman buffer and exposed Bulgaria to the Golden Horde. Successive governments attempted to prevent simultaneous wars on several fronts. In 1255 Tsar Michael married a granddaughter of the Hungarian king, renounced claims to Beograd and Branichevo and secured an alliance with Hungary so that Bulgarian forces could concentrate on Nicaea and Macedonia. After costly campaigns, Nicaea recovered the disputed territories by July 1256; peace was mediated by Michael’s new father-in-law, Rostislav of Mačva. Marriage diplomacy had bought strategic freedom, but it also drew Hungarian-connected dynasts directly into Bulgarian succession politics.

The murder of Michael and the rapid fall of Koloman in 1256–1257 exposed this danger. Koloman forcibly married Michael’s widow, Rostislav’s daughter, to strengthen his own claim, but failed to consolidate power. Rostislav invaded, later established himself at Vidin and, with Hungarian recognition, assumed the title of tsar of Bulgaria. Another claimant, Mico, appeared in the southeast. Under Constantine Tih, Tarnovo therefore had to balance Nicaea, Hungary and rival Bulgarian centers. An alliance with Nicaea was sealed by Constantine’s marriage to Irene in 1258 and confirmed when George Akropolites visited Tarnovo around January 1260. The resulting peace lasted from 1258 to 1262 and allowed Constantine to concentrate on the Hungarian-supported threat in the northwest.

The recovery of Constantinople by Michael VIII Palaiologos in 1261 changed the relationship. Nicaea again became Byzantium, while the blinding of John IV Laskaris, a relative of Constantine’s wife Irene, sharpened hostility toward Michael VIII. War in 1262–1263 cost Bulgaria fortresses in western Thrace and along the Black Sea. At the same time Vidin passed under the Hungarian protection of Jacob Svetoslav, who accepted Hungarian suzerainty for Vidin and his other territories. Faced with stronger enemies to the south and northwest, Constantine accepted western losses and sought peace with Hungary so that he could concentrate on Byzantium. The episode illustrates a recurring Bulgarian dilemma: diplomatic concentration on one frontier often required recognition of damaging faits accomplis on another.

Steppe diplomacy now became unavoidable. Constantine appealed to his Tatar overlords against Byzantium, but the Golden Horde was divided. Khan Berke had offered some protection before his death in 1265; his successor Möngke Temür exercised weaker control, while Nogai emerged as an increasingly autonomous power near Bulgaria. Byzantium itself cultivated steppe alliances and, after Constantine raided Thrace around 1271, called on Nogai, whose forces crossed the Danube and devastated Bulgaria. Encircled by Byzantium, Hungary and Nogai, Constantine made peace but joined Charles of Anjou’s anti-Byzantine coalition in 1272 or 1273 when the opportunity arose. This western alignment offered a diplomatic counterweight, yet Bulgaria’s exposed position prevented effective action. By the reign of George I Terter, Nogai’s predominance had produced the period of greatest Tatar interference, from about 1280 until Nogai’s death in 1299.

Byzantium repeatedly used dynastic claimants and aristocratic exiles as instruments of intervention. Its attempt to install Ivan Asen III at Tarnovo failed when Ivaylo defeated invading Byzantine armies and the imperial candidate fled. George I Terter then sought accommodation. After the Sicilian Vespers removed Charles of Anjou as an effective counterweight, Bulgaria lacked the strength to recover Thrace or the Black Sea coast without assistance. In 1284 Andronikos II recognized George as tsar of Bulgaria and granted him the Byzantine court title of despot. The treaty represented mutual realism: Byzantium abandoned an unsuccessful candidate, while Bulgaria recognized that peace was preferable to an unwinnable attempt to recover disputed lands.

A more successful combination of war, peace and commerce appeared under Theodore Svetoslav. Bulgarian victory over the Byzantines at the Skafida River in 1304 was followed, before 2 April 1307, by a durable peace that legalized Bulgarian gains made between 1304 and 1307. The agreement allowed Byzantium to turn against the Catalan danger and schemes to restore the Latin Empire, while Bulgaria stabilized its international and domestic position. Theodore’s marriage to Theodora Palaiologina helped sustain the settlement and provided a channel for influence at the Byzantine court; at her request, her father Michael IX ordered in 1318 that properties taken from the Bulgarian monastery of Zographou be restored. The recovered Black Sea ports expanded trade carried in Venetian and Genoese ships, chiefly exporting agricultural produce and importing luxury goods. Increased commerce was accompanied by much larger issues of Bulgarian coinage and strengthened the monarchy’s economic basis.

The rise of Serbia posed a different challenge. Bulgarian influence in Macedonia had already receded while Serbian expansion advanced southward. Michael III Shishman Asen attempted to confront this altered balance, but the Bulgarian defeat by Serbia at Velbazhd on 28 July 1330 ended with his death and enabled Serbia to support Ivan Stefan’s accession. Ivan Stefan was soon expelled by an anti-Serbian revolt, and Ivan Alexander became tsar in 1331. His initial victory over Andronikos III at Rusokastro on 18 July 1331 restored several southeastern towns and checked Byzantine pressure. He then secured his western frontier through the marriage of his sister Elena to Stefan Dušan on 19 April 1332. The marriage inaugurated a Bulgarian-Serbian peace that endured, but it also left Dušan free to expand through Macedonia while Bulgaria turned once more toward Thrace.

During the Byzantine civil war of 1341–1347, Ivan Alexander participated energetically but pursued limited territorial objectives. An agreement with the Constantinopolitan regency brought Bulgaria lands around Plovdiv, Perushtitsa, Tsepina, Stenimaka and toward Kosnik in 1344. Yet while Bulgaria concentrated on eastern Thrace, Dušan occupied most of Macedonia, Albania and parts of Epiros and Thessaly. Ivan Alexander did not combine his efforts with the independent Rhodope ruler Momchil, whose principality disappeared in 1345, and he declined John Kantakouzenos’s proposal for joint action against the Turks under Serbian influence. The Tarnovo patriarch Simeon participated in Dušan’s imperial coronation at Skopje in April 1346, publicly acknowledging the emergence of a Serbian empire modeled partly on Bulgarian and Byzantine traditions. The peace with Serbia protected Bulgaria’s western border, but its strategic price was the abandonment of effective competition for Macedonia.

Ivan Alexander attempted to escape this increasingly narrow Balkan framework through maritime diplomacy. Venice had traded in Bulgarian lands since the late thirteenth century and established colonies at Varna, Mesembria, Anchialos and Sozopolis, purchasing grain, hides, wax and honey. A treaty in 1346 or 1347 formally regulated relations, and the tsar confirmed the connection in a letter to Doge Andrea Dandolo dated 4 October 1352. Bulgaria also opened less formal relations with Genoa: in May 1352 two envoys of the Genoese admiral Paganino Doria set out for Bulgaria while his fleet fought Venice in the Bosporus. Contact with both republics stimulated trade and broadened Bulgaria’s international connections, but it also drew the Black Sea coast into the rivalry of foreign maritime powers. In the later Dobruja polity, Ivanko’s treaty of 1387 granted extensive privileges to Genoa and may also have been directed against Tarnovo’s Venetian connection.

Dynastic policy within Ivan Alexander’s own household, however, accelerated political division. After marrying Theodora, a converted Jewish woman, he displaced Ivan Stratsimir, the son of his first marriage, in favor of Ivan Shishman. Shortly before 1360 Stratsimir received Vidin, which developed into a separate principality and then a царство with its own coinage and diplomacy. In northeastern Bulgaria the territories of Balik and his successor Dobrotitsa likewise moved from appanage toward independence. Thus three Bulgarian political centers emerged: Tarnovo, Vidin and Dobruja. Their rulers could negotiate separately with Hungary, Byzantium, Wallachia, Genoa and the patriarchate of Constantinople, but this diplomatic pluralism represented the disintegration of central authority rather than a coordinated federal strategy.

The Hungarian conquest of Vidin in 1365 demonstrated both the dangers of division and the continuing value of coalition diplomacy. King Louis I captured the city on 2 June, imprisoned Ivan Stratsimir and his family, established a Hungarian administration and promoted Catholic conversion. In 1366 Ivan Alexander refused passage through Bulgaria to Emperor John V Palaiologos on his return from seeking western assistance against the Turks. John’s cousin, Count Amadeus VI of Savoy, retaliated along the Bulgarian Black Sea coast, taking Agathopolis, Skafida, Sozopolis, Anchialos, Mesembria and Emona and besieging Varna. Negotiations, in which Dobrotitsa played an important role, secured John V’s passage and ended the siege. Dobrotitsa received Varna, Emona and Kozyak, while the abandoned coastal towns passed to John V, who undertook to help liberate Vidin. He supplied 180,000 florins to the Wallachian voivode Vladislav Vlaicu for operations against Hungary. Vidin was restored in 1369, but Ivan Stratsimir returned as Louis’s vassal; Hungarian guarantees, including the retention of his daughters at court, strengthened his independence from Tarnovo.

By then the Ottoman advance had displaced Byzantium as the central problem of Bulgarian diplomacy. Turks first employed as allies in Byzantine civil wars became enemies of all the Balkan states; they established a permanent base at Gallipoli in 1354, took Didymoteichon around 1359–1361 and held Adrianople by about 1368–1369. Bulgaria, Byzantium and Serbia nevertheless remained divided. After Ivan Alexander’s death on 17 February 1371 and the defeat of Balkan forces at Chernomen on 26 September, Ivan Shishman became a vassal of Sultan Murad I. Tarnovo Bulgaria formed a temporary shield between the Ottomans and Vidin, while dynastic concessions, including the fate of Ivan Shishman’s sister Kera Tamara, helped preserve an insecure peace. Traditional Bulgarian-Byzantine rivalry now lost much of its practical meaning: the Ottoman ruler, rather than the Byzantine emperor, increasingly determined the conditions under which Bulgarian rulers could survive.

The final diplomatic landscape was consequently one of separate Bulgarian courts pursuing separate accommodations. Ivan Stratsimir asserted full tsarist status and transferred the Vidin church from Tarnovo to the jurisdiction of Constantinople. Dobrotitsa acted as an autonomous Black Sea ruler, allied with Ivan Alexander against Hungary but later pursued his own relations with Byzantium; in November 1373 his unnamed daughter married Michael Palaiologos, son of John V. His successor Ivanko turned to Genoa, while Wallachia and Byzantine appanage holders subsequently competed for Dobruja under the shadow of Ottoman suzerainty. Tarnovo fell on 17 July 1393, Ivan Shishman was executed on 29 October 1395, and the defeat of King Sigismund’s crusading army at Nicopolis on 25 September 1396 was followed by the conquest of Vidin and the captivity of Ivan Stratsimir. The diplomatic history of the Second Bulgarian Empire had thus moved from the pursuit of universal recognition and Balkan hegemony to a struggle for local survival. Its rulers had repeatedly used crowns, marriages, embassies, church jurisdiction, commercial privileges and shifting alliances with sophistication, but no diplomatic instrument could compensate indefinitely for territorial fragmentation and the rise of an imperial power able to dominate every remaining Bulgarian center separately.

The revived Bulgarian state entered international politics with a bold set of ideas. Its rulers wanted more than freedom from Byzantium. They also wanted other states to accept a sovereign Bulgarian monarchy and a Bulgarian church. The title especially linked with Kaloyan, ruler of Bulgaria and Vlachia, showed claims over Moesia, parts of Thrace and Macedonia, and the lands north of the Danube then called Vlachia. But this new monarchy did not enjoy unquestioned legitimacy, and its borders were not secure. Bulgarian diplomacy therefore mixed appeals to the old imperial Bulgarian past with practical deals with powers outside the Orthodox Byzantine world.

Kaloyan’s dealings with the papacy show this search for recognition most clearly. He did not think a crown given only by the archbishop of Tarnovo was enough to make his rule fully accepted abroad, so he turned to Rome. Papal recognition and the royal crown he received in 1204 strengthened his position just as the Fourth Crusade destroyed Byzantine rule in Constantinople and created the Latin Empire. Kaloyan could now present himself as a ruler accepted beyond the Balkans, while also taking advantage of the political void left by Byzantium’s collapse. His conquests in Macedonia and Thrace went together with church policy: Greek bishops seen as unreliable were removed and replaced with Slavic clergy, and people considered suspect were moved to the Danubian lands. In this way diplomacy, conquest and church policy all worked together to strengthen Bulgarian sovereignty.

Even so, relations with the Latin Empire showed that recognition did not mean lasting friendship. Bulgaria and the crusader regime became rivals for the Byzantine inheritance, and Kaloyan’s successors had to balance between the Latins, Hungary and the Greek successor states. Under Boril, who was weakened by internal rivals and breakaway regional lords, Bulgaria moved close to Hungary around 1213 and got Hungarian help against a revolt at Vidin. Boril also kept an alliance with the Latin emperor Henry, while a planned marriage in 1214 between Boril’s daughter and the future Béla IV was meant to deepen ties with Hungary. These arrangements limited the freedom of separatists such as Alexios Slav, who replied by turning toward Epiros and sealing that new connection through marriage in 1216. Dynastic marriage had already become one of the main ways Bulgarian rulers and regional lords changed sides in diplomacy.

Ivan Asen II’s rise in 1218 changed Bulgaria’s position. When the returning Hungarian king Andrew II reached the Bulgarian frontier late that year, Ivan Asen held him back and let him continue only after he accepted a marriage between the Bulgarian ruler and his daughter Maria. The wedding took place early in 1221. This was not just a family matter: Beograd and Branichevo, disputed Danubian strongholds, seem to have passed to Ivan Asen as Maria’s dowry. In this way marriage diplomacy achieved what war might have made expensive, and for a time it restored Bulgarian control in a region disputed with Hungary throughout the thirteenth century.

At first, Ivan Asen II watched the struggle among the Latin Empire, Epiros, Nicaea and the Bulgarian state from a strong position. Epiros had become the strongest power in the Balkans under Theodore, but its defeat by Ivan Asen in 1230 ended its imperial lead. Bulgarian power then reached into Greek, Albanian and Serbian lands, and another dynastic link tied Ivan Asen’s family to the Serbian ruler Stefan Vladislav. The victory did more than enlarge Bulgaria. It changed the balance among the successor states competing for Constantinople and let Tarnovo claim leadership in the Orthodox world. The older formula that included Vlachia faded, while the monarchy’s political thinking moved more directly toward Bulgarian leadership among Orthodox states.

Trade policy supported this expansion. In 1230 Ivan Asen II gave Dubrovnik a charter that allowed Ragusan merchants to trade freely in Bulgarian cities, including Beograd and Branichevo. This showed both how far Bulgarian claims reached and how ready the crown was to use privileges for foreign merchants to encourage trade and link distant towns to the monarchy. Access to Adriatic traders widened Bulgaria’s diplomatic reach beyond its nearby land borders. These commercial agreements were not separate from high politics. They advertised control over disputed provinces, brought in customs revenue and gave foreign communities a stake in the stability of Bulgarian rule.

The struggle for Constantinople soon forced Ivan Asen to rethink his partners. After John of Brienne took power in the Latin capital in 1231, Bulgaria opened talks with Nicaea and in 1232 joined it against the Latin Empire. Hungary, a Catholic protector of the Latin regime, answered by taking Beograd and Branichevo and besieging Vidin in 1232; although a Bulgarian relief army was beaten, Vidin itself held out. In 1234 Ivan Asen’s daughter was promised to the Nicaean heir, and in 1235 the Bulgarian and Nicaean courts met at Gallipoli. The agreement included major church concessions: Tarnovo gave up claims over Thessaloniki, Mount Athos and eastern Thrace, and recognized the Nicaean patriarch as ecumenical patriarch, that is, the senior Orthodox patriarch. The marriage alliance and church settlement made joint action against Constantinople possible.

Still, Ivan Asen’s diplomacy stayed flexible rather than fixed. During the siege of Constantinople in 1235–1236, he saw that a Nicaean victory would bring a strong Greek empire back to the city, which might threaten Bulgaria more than the weak Latin regime did. He therefore broke the alliance, demanded the return of his daughter and brought in Cuman forces against Nicaea. By the end of his reign he had again improved relations with Hungary and, indirectly, with the Latin Empire. The rise of the Tatars gave him a strong reason for this shift: the destruction of the Cuman state in 1238–1239 and the conquest of Kiev in 1240 placed a powerful steppe force on the borders of both Bulgaria and Hungary. A Bulgarian envoy was warmly received by King Béla in the first months of 1240, which shows that both sides were moving toward joint defense against a danger greater than their quarrels along the Danube.

After Ivan Asen’s death, this diplomatic system became harder to control. Young rulers, fighting regents and provincial boyars weakened the personal ties that held the realm together, while the Mongol-Tatar invasions of 1241–1242 destroyed the friendly Cuman buffer and exposed Bulgaria to the Golden Horde. Later governments tried to stop wars on several fronts at once. In 1255 Tsar Michael married a granddaughter of the Hungarian king, gave up claims to Beograd and Branichevo and secured an alliance with Hungary so that Bulgarian forces could focus on Nicaea and Macedonia. After costly campaigns, Nicaea regained the disputed territories by July 1256; peace was arranged by Michael’s new father-in-law, Rostislav of Mačva. Marriage diplomacy had won time for Bulgaria, but it also pulled Hungarian-linked dynasts directly into Bulgarian struggles over the succession.

The murder of Michael and the quick fall of Koloman in 1256–1257 exposed that risk. Koloman forced Michael’s widow, Rostislav’s daughter, to marry him in order to strengthen his own claim, but he failed to secure his rule. Rostislav invaded, later made himself ruler at Vidin and, with Hungarian recognition, took the title of tsar of Bulgaria. Another claimant, Mico, appeared in the southeast. Under Constantine Tih, Tarnovo therefore had to juggle Nicaea, Hungary and rival Bulgarian power centers. An alliance with Nicaea was fixed by Constantine’s marriage to Irene in 1258 and confirmed when George Akropolites visited Tarnovo around January 1260. The peace that followed lasted from 1258 to 1262 and let Constantine focus on the Hungarian-backed threat in the northwest.

The recovery of Constantinople by Michael VIII Palaiologos in 1261 changed everything. Nicaea became Byzantium again, and the blinding of John IV Laskaris, a relative of Constantine’s wife Irene, deepened hostility to Michael VIII. War in 1262–1263 cost Bulgaria fortresses in western Thrace and along the Black Sea. At the same time Vidin came under the Hungarian protection of Jacob Svetoslav, who accepted Hungarian overlordship for Vidin and his other lands. Faced with stronger enemies in the south and northwest, Constantine accepted losses in the west and looked for peace with Hungary so he could concentrate on Byzantium. This shows a pattern that returned again and again in Bulgarian diplomacy: making progress on one frontier often meant accepting losses on another.

At this point, steppe politics could no longer be avoided. Constantine called on his Tatar overlords against Byzantium, but the Golden Horde was divided. Khan Berke had offered some protection before his death in 1265; his successor Möngke Temür had less control, while Nogai emerged as a more independent power near Bulgaria. Byzantium itself worked with steppe allies, and after Constantine raided Thrace around 1271, it summoned Nogai, whose troops crossed the Danube and devastated Bulgaria. Surrounded by Byzantium, Hungary and Nogai, Constantine made peace but joined Charles of Anjou’s anti-Byzantine coalition in 1272 or 1273 when the chance came. This western alignment gave him another diplomatic counterweight, but Bulgaria’s exposed position kept him from acting effectively. By the reign of George I Terter, Nogai’s dominance had brought the period of heaviest Tatar interference, from about 1280 until Nogai’s death in 1299.

Byzantium repeatedly used rival claimants and noble exiles as tools of intervention. Its attempt to place Ivan Asen III on the throne at Tarnovo failed when Ivaylo defeated the invading Byzantine armies and the imperial candidate fled. George I Terter then looked for accommodation. After the Sicilian Vespers removed Charles of Anjou as a real counterweight, Bulgaria lacked the strength to win back Thrace or the Black Sea coast without help. In 1284 Andronikos II recognized George as tsar of Bulgaria and gave him the Byzantine court title of despot, a high honor at court. The treaty was an act of mutual realism: Byzantium gave up on an unsuccessful candidate, while Bulgaria accepted that peace was better than an unwinnable attempt to regain the disputed lands.

A more effective mix of war, peace and trade came under Theodore Svetoslav. Bulgarian victory over the Byzantines at the Skafida River in 1304 was followed, before 2 April 1307, by a lasting peace that confirmed the Bulgarian gains made between 1304 and 1307. The agreement let Byzantium turn to the Catalan threat and to plans to restore the Latin Empire, while Bulgaria steadied both its foreign and internal position. Theodore’s marriage to Theodora Palaiologina helped keep the settlement in place and gave him a channel for influence at the Byzantine court; at her request, her father Michael IX ordered in 1318 that property taken from the Bulgarian monastery of Zographou be returned. The recovered Black Sea ports increased trade carried on Venetian and Genoese ships, mostly exporting farm goods and importing luxury items. Growing trade also brought much larger coin issues and strengthened the monarchy’s financial base.

The rise of Serbia created a different problem. Bulgarian influence in Macedonia had already declined as Serbian expansion pushed south. Michael III Shishman Asen tried to meet this new balance, but Bulgaria’s defeat by Serbia at Velbazhd on 28 July 1330 ended with his death and allowed Serbia to support Ivan Stefan’s accession. Ivan Stefan was soon driven out by an anti-Serbian revolt, and Ivan Alexander became tsar in 1331. His first victory over Andronikos III at Rusokastro on 18 July 1331 restored several towns in the southeast and checked Byzantine pressure. He then secured his western border through the marriage of his sister Elena to Stefan Dušan on 19 April 1332. This began a Bulgarian-Serbian peace that lasted, but it also left Dušan free to expand through Macedonia while Bulgaria turned again toward Thrace.

During the Byzantine civil war of 1341–1347, Ivan Alexander took part actively, but he aimed for limited gains. An agreement with the Constantinopolitan regency gave Bulgaria lands around Plovdiv, Perushtitsa, Tsepina, Stenimaka and toward Kosnik in 1344. Yet while Bulgaria focused on eastern Thrace, Dušan seized most of Macedonia, Albania and parts of Epiros and Thessaly. Ivan Alexander did not join forces with the independent Rhodope ruler Momchil, whose principality disappeared in 1345, and he rejected John Kantakouzenos’s proposal for joint action against the Turks under Serbian influence. The Tarnovo patriarch Simeon took part in Dušan’s imperial coronation at Skopje in April 1346, openly recognizing the rise of a Serbian empire shaped in part by Bulgarian and Byzantine tradition. Peace with Serbia protected Bulgaria’s western frontier, but it also meant giving up any real contest for Macedonia.

Ivan Alexander then tried to move beyond this tightening Balkan frame through maritime diplomacy. Venice had traded in Bulgarian lands since the late thirteenth century and had colonies at Varna, Mesembria, Anchialos and Sozopolis, where it bought grain, hides, wax and honey. A treaty in 1346 or 1347 formally set out the relationship, and the tsar confirmed it in a letter to Doge Andrea Dandolo dated 4 October 1352. Bulgaria also opened less formal ties with Genoa: in May 1352 two envoys of the Genoese admiral Paganino Doria set off for Bulgaria while his fleet fought Venice in the Bosporus. Contact with both republics boosted trade and widened Bulgaria’s international links, but it also pulled the Black Sea coast into the rivalry of foreign sea powers. In the later Dobruja polity, Ivanko’s treaty of 1387 gave large privileges to Genoa and may also have been meant as a reply to Tarnovo’s Venetian ties.

Inside Ivan Alexander’s own family, however, dynastic policy sped up political splitting. After marrying Theodora, a converted Jewish woman, he pushed aside Ivan Stratsimir, the son of his first marriage, in favor of Ivan Shishman. Shortly before 1360 Stratsimir received Vidin, which grew into a separate principality and then a царство, that is, a kingdom-like realm, with its own coinage and diplomacy. In northeastern Bulgaria, the lands of Balik and his successor Dobrotitsa also moved from appanage, or a granted family holding, toward independence. Three Bulgarian political centers now existed: Tarnovo, Vidin and Dobruja. Their rulers could negotiate separately with Hungary, Byzantium, Wallachia, Genoa and the patriarchate of Constantinople, but this was not a planned federal system. It was a sign that central power was breaking apart.

The Hungarian conquest of Vidin in 1365 showed both the danger of division and the continuing importance of coalition diplomacy. King Louis I took the city on 2 June, imprisoned Ivan Stratsimir and his family, set up a Hungarian administration and pushed Catholic conversion. In 1366 Ivan Alexander refused to let Emperor John V Palaiologos pass through Bulgaria on his way home after seeking western help against the Turks. John’s cousin, Count Amadeus VI of Savoy, struck back along the Bulgarian Black Sea coast, taking Agathopolis, Skafida, Sozopolis, Anchialos, Mesembria and Emona and besieging Varna. Negotiations, in which Dobrotitsa played a major part, secured John V’s passage and ended the siege. Dobrotitsa received Varna, Emona and Kozyak, while the abandoned coastal towns passed to John V, who promised to help free Vidin. He gave 180,000 florins to the Wallachian voivode Vladislav Vlaicu for operations against Hungary. Vidin was restored in 1369, but Ivan Stratsimir returned as Louis’s vassal; Hungarian guarantees, including keeping his daughters at court, made him less dependent on Tarnovo.

By then, the Ottoman advance had replaced Byzantium as the main issue in Bulgarian diplomacy. Turks first used as allies in Byzantine civil wars became enemies of all the Balkan states; they set up a lasting base at Gallipoli in 1354, took Didymoteichon around 1359–1361 and held Adrianople by about 1368–1369. Even so, Bulgaria, Byzantium and Serbia stayed divided. After Ivan Alexander’s death on 17 February 1371 and the defeat of Balkan forces at Chernomen on 26 September, Ivan Shishman became a vassal of Sultan Murad I. Tarnovo Bulgaria became a temporary barrier between the Ottomans and Vidin, while dynastic concessions, including what happened to Ivan Shishman’s sister Kera Tamara, helped preserve an uneasy peace. The old Bulgarian-Byzantine rivalry now mattered much less in practice. The Ottoman ruler, not the Byzantine emperor, increasingly set the terms on which Bulgarian rulers could survive.

The final diplomatic picture was therefore one of separate Bulgarian courts making separate bargains. Ivan Stratsimir claimed full tsar status and moved the Vidin church from Tarnovo to the authority of Constantinople. Dobrotitsa acted as an independent Black Sea ruler, allied with Ivan Alexander against Hungary but later made his own deals with Byzantium; in November 1373 his unnamed daughter married Michael Palaiologos, son of John V. His successor Ivanko turned to Genoa, while Wallachia and Byzantine appanage holders later competed for Dobruja under Ottoman overlordship. Tarnovo fell on 17 July 1393, Ivan Shishman was executed on 29 October 1395, and King Sigismund’s crusading army was defeated at Nicopolis on 25 September 1396, after which Vidin was conquered and Ivan Stratsimir was taken captive. The diplomatic history of the Second Bulgarian Empire had thus moved from a quest for universal recognition and Balkan dominance to a struggle for local survival. Its rulers repeatedly used crowns, marriages, embassies, church authority, trade privileges and changing alliances with great skill, but no diplomatic tool could make up forever for territorial fragmentation and for the rise of an imperial power able to dominate each remaining Bulgarian center one by one.

After Bulgaria was restored, its rulers wanted more than just freedom from Byzantium. They wanted other countries to accept their state, church, and rulers as fully equal. So they used crowns, marriages, trade deals, and changing alliances to protect Bulgaria and make it stronger.

Kaloyan was the first to do this in a big way. In 1204 he got papal recognition and a royal crown from Rome. This helped him gain status after the Fourth Crusade broke Byzantine power in Constantinople. He also pushed Greek church leaders out of some lands and replaced them with Slavic clergy.

Under Ivan Asen II, Bulgaria became much stronger. In 1230 he defeated Epiros at Klokotnitsa and expanded Bulgarian power into Greek, Albanian, and Serbian lands. He also made trade deals, such as one with Dubrovnik in 1230, to bring wealth and connect Bulgaria to the Adriatic world.

Ivan Asen II also used alliances carefully. He first worked with Nicaea against the Latin Empire, then broke away when that became risky. He later married his daughter into the Nicaean ruling family and won peace, but he was always ready to switch sides if Bulgaria needed to avoid danger from a stronger neighbor.

After Ivan Asen II died, Bulgaria became less stable. Mongol attacks in the 1240s made the country more exposed. Later rulers had to deal with threats from Hungary, Byzantium, and Serbia at the same time. Marriage ties helped sometimes, but they also pulled foreign powers deeper into Bulgarian politics.

A new strong ruler came with Theodore Svetoslav, who made peace with Byzantium after a victory in 1304. Later, under Ivan Alexander, Bulgaria tried to recover lost ground, but Serbia grew stronger and won a major victory at Velbazhd in 1330. Ivan Alexander then focused more on the east and made peace with Serbia through a marriage in 1332.

In the mid-1300s, Bulgaria also split into separate centers of power, including Tarnovo, Vidin, and Dobruja. This weakened the state. Hungary took Vidin in 1365, and Byzantium and other powers also вмешались in Bulgarian affairs. Trade with Venice and Genoa grew, but it did not stop the political break-up.

By the end of the century, the Ottomans had become the main danger. They defeated Balkan forces in 1371, and Bulgarian rulers had to accept Ottoman pressure to survive. Tarnovo fell in 1393, Ivan Shishman was killed in 1395, and Vidin fell after the battle of Nicopolis in 1396. Bulgaria’s rulers had been skilled diplomats, but they could not hold the state together against outside powers and internal division.