Ivan Alexander of Bulgaria Ivan Alexander ( , transliterated " Ivan Aleksandǎr " ; pronounced ; original spelling : ) , also known as John Alexander , ruled as Emperor ( " Tsar " ) of Bulgaria from 1331 to 1371 , during the Second Bulgarian Empire . The date of his birth is unknown . He died on 17 February 1371 . The long reign of Ivan Alexander is considered a transitional period in Bulgarian medieval history . Ivan Alexander began his rule by dealing with internal problems and external threats from Bulgaria ' s neighbours , the Byzantine Empire and Serbia , as well as leading his empire into a period of economic recovery and cultural and religious renaissance . However , the emperor was later unable to cope with the mounting incursions of Ottoman forces , Hungarian invasions from the northwest and the Black Death . In an ill - fated attempt to combat these problems , he divided the country between his two sons , thus forcing it to face the imminent Ottoman conquest weakened and divided . Early rule . Ivan Alexander was the son of the " despotēs " Sracimir of Krǎn by Petrica , a sister of Michael Asen III of Bulgaria . Therefore , Ivan Alexander was a nephew of Michael Asen III . Paternally , Ivan Alexander descended from the Asen dynasty . By 1330 Ivan Alexander was himself a " despotēs " and governed the city of Loveč . Together with his father and his father - in - law Basarab of Wallachia , Ivan Alexander fought in the Battle of Velbǎžd against the Serbs at modern - day Kjustendil in 1330 , in which Bulgaria suffered defeat . The defeat , combined with the worsening relations with the Byzantine Empire , precipitated an internal crisis , which was exacerbated by an invasion of the Byzantines . A coup d ' état drove Ivan Stefan out of the capital Tǎrnovo in 1331 , and the conspirators placed Ivan Alexander on the throne . The new ruler set about consolidating his position by regaining territories recently lost to the Byzantine Empire . In 1331 Ivan Alexander campaigned around Adrianople and reconquered northeastern Thrace . Meanwhile , Stefan Uroš IV Dušan deposed his father Stefan Uroš III Dečanski and became Serbian king in 1331 . This helped normalize the previously tense relations between the two countries . Ivan Alexander and Stefan Uroš IV Dušan concluded an alliance , which was cemented by the marriage of the Serbian king to Helena of Bulgaria , a sister of Ivan Alexander , on Easter 1332 . At about the same time , Belaur , a brother of Michael Asen III , rebelled in Vidin , probably in support of his deposed nephew Ivan Stefan ' s claim to the throne . The advance of the Byzantine Emperor Andronikos III Palaiologos against Bulgaria in the summer of 1332 protracted military operations against the rebels . The Byzantines overran Bulgarian - controlled northeastern Thrace , but Ivan Alexander rushed southward with a small army and swiftly caught up with Andronikos III at Rusokastro . After giving the impression that he wished to negotiate , Ivan Alexander , reinforced by Mongol cavalry , overwhelmed the smaller but better organized Byzantine army in the Battle of Rusokastro . The contested cities surrendered to Ivan Alexander , while Andronikos III sought refuge within the walls of Rusokastro . The war ended with Ivan Alexander meeting Andronikos and agreeing a peace based on the " status quo " . To seal the alliance , he betrothed his eldest son , Michael Asen IV , to Andronikos ' s daughter Maria ( Eirene ) , the marriage eventually taking place in 1339 . The Bulgarian emperor was now free to turn his attentions to Belaur , but it was not until 1336 or 1337 that the rebellion in the northwest was put down . In about 1332 Ivan Alexander had crowned his eldest son Michael Asen IV co - emperor , perhaps to safeguard possession of the throne by his own family . He followed up this traditional association with the coronation of his younger sons Ivan Sracimir and Ivan Asen IV in 1337 . Ivan Alexander may have intended the creation of two younger co - emperors to establish immediate control over important cities and regions , as Ivan Sracimir was eventually based in Vidin , and Ivan Asen IV perhaps in Preslav . Nevertheless , this was a marked departure from Byzantine practice , in which younger sons of the sovereign were made " despotēs " , whether they were charged with a territorial administration or not . Relations with the Byzantine Empire . In the early 1340s relations with the Byzantine Empire temporarily deteriorated . Ivan Alexander demanded the extradition of his cousin Šišman , one of the sons of Michael Asen III , threatening the Byzantine government with war . Ivan Alexander ' s show of force backfired , as the Byzantines managed to see through his intentions and sent against him the fleet of their ally , the Turkish emir of Smyrna Umur Beg . Landing in the Danube Delta , they pillaged the countryside and attacked nearby Bulgarian cities . Forced to restrain his demands , Ivan Alexander invaded the Byzantine Empire again at the end of 1341 , claiming that he was summoned by the people of Adrianople . However , Ivan Alexander ' s troops were defeated twice by Turkish allies of the Byzantines near the city . In 1341 – 1347 the Byzantine Empire was plunged into a protracted civil war between the regency for Emperor John V Palaiologos under Anna of Savoy and his intended guardian John VI Kantakouzenos . The neighbours of the Byzantines took advantage of the civil war , and while Stefan Uroš IV Dušan of Serbia sided with John VI Kantakouzenos , Ivan Alexander backed John V Palaiologos and his regency . Although the two Balkan rulers picked opposite sides in the Byzantine civil war , they maintained their alliance with each other . As the price for Ivan Alexander ' s support , the regency for John V Palaiologos ceded him the city of Philippopolis ( Plovdiv ) and nine important fortresses in the Rhodope Mountains in 1344 . This peaceful turnover constituted the last major success of Ivan Alexander ' s foreign policy . Rise of Serbia and the Ottoman threat . During the same period , the Serbian king took advantage of the Byzantine civil war to take possession of what is now Macedonia , and of most of Albania and northern Greece . In 1345 he began to call himself " Emperor of Serbs and Greeks " , and in 1346 he was crowned as such by the newly created Patriarch of Serbia . These actions , which the Byzantines received with indignation , appear to have been supported by Bulgaria , as the Patriarch of Bulgaria Simeon had participated in both the creation of a Serbian patriarchate and the imperial coronation of Stefan Uroš IV Dušan . By the second half of the 1340s , little remained of Ivan Alexander ' s initial successes . John VI Kantakouzenos ' Turkish allies pillaged parts of Bulgarian Thrace in 1346 , 1347 , 1349 , 1352 and 1354 , to which were added the ravages of the Black Death . The Bulgarians ' attempts to repel the invaders met with repeated failure , and Ivan Alexander ' s third son and co - emperor , Ivan Asen IV , was killed in battle against the Turks in 1349 , as was his older brother Michael Asen IV in 1355 or a little earlier . By 1351 the Byzantine civil war was over , and John VI Kantakouzenos had realized the threat posed by the Ottomans to the Balkan Peninsula . He appealed to the rulers of Serbia and Bulgaria for a united effort against the Turks and asked Ivan Alexander for money to construct warships , but his appeals fell on deaf ears as his neighbours distrusted his intentions . A new attempt for cooperation between Bulgaria and the Byzantine Empire followed in 1355 , after John VI Kantakouzenos had been forced to abdicate and John V Palaiologos had been established as supreme emperor . To cement the treaty , Ivan Alexander ' s daughter Keraca Marija was married off to the future Byzantine Emperor Andronikos IV Palaiologos , but the alliance failed to produce concrete results . Further stability problems and external conflicts . At home Ivan Alexander compromised the internal stability of his realm by divorcing his first wife Theodora of Wallachia ( in about 1349 ) and marrying a converted Jew , also named Theodora . The new marriage produced new sons , whom Ivan Alexander proceeded to crown co - emperors , Ivan Šišman in about 1356 and Ivan Asen V by 1359 . Ivan Alexander ' s last surviving son from his first marriage , the co - emperor Ivan Sracimir , became effectively independent around 1356 ; and Ivan Alexander ' s control over other powerful vassals , such as the rulers of Wallachia and Dobruja , who pursued their own foreign policies , was hardly stronger . From the middle of the 14th century , Bulgaria fell prey to the aspirations of the Angevin king Louis I of Hungary , who annexed Moldavia in 1352 and established a vassal principality there , before conquering Vidin in 1365 , and taking Ivan Sratsimir and his family into captivity . In the meantime Bulgarians and Byzantines had clashed again in 1364 . In 1366 , when Emperor John V Palaiologos was returning from his trip to the west , the Bulgarians refused to let him pass through Bulgaria . This stance backfired , as another Byzantine ally , Count Amadeus VI of Savoy , leading the Savoyard crusade , captured several Bulgarian maritime cities in retaliation , including Ankhialos ( Pomorie ) and Mesembria ( Nesebǎr ) , though he failed to take Varna . Outmanoeuvred , Ivan Alexander was forced to make peace . The captured cities were turned over to the Byzantine Empire , while Emperor John V Palaiologos paid the sum of 180 , 000 florins to Ivan Alexander . The Bulgarian emperor used this sum and territorial concessions to induce his at least " de jure " vassals Dobrotica of Dobruja and Vladislav I of Wallachia to reconquer Vidin from the Hungarians . The war was successful , and Ivan Sracimir was reinstalled in Vidin in 1369 , although the Hungarian king forced him to acknowledge his overlordship . The relatively successful resolution of the crisis in the northwest did nothing to help recover the losses in the southeast . To make matters worse , in 1369 ( the date is disputed ) , the Ottoman Turks under Murad I conquered Adrianople ( in 1363 ) and made it the effective capital of their expanding state . At the same time , they also captured the Bulgarian cities of Philippopolis and Boruj ( Stara Zagora ) . As Bulgaria and the Serbian princes in Macedonia prepared for united action against the Turks , Ivan Alexander died on February 17 , 1371 . He was succeeded by his sons Ivan Sracimir in Vidin and Ivan Šišman in Tǎrnovo , while the rulers of Dobruja and Wallachia achieved further independence . Culture and religion . During Ivan Alexander ' s rule , the Second Bulgarian Empire entered a period of cultural renaissance , which is sometimes referred to as the " Second Golden Age of Bulgarian culture " , the original one being the rule of Simeon the Great . A large number of Bulgarian monasteries and churches were constructed or renovated on the order of Ivan Alexander . Mural portraits of him as a donor can be seen in the Bachkovo Monastery ' s ossuary and in the Rock - hewn Churches of Ivanovo . Donor ' s deeds of Ivan Alexander prove that the monasteries of the Holy Mother of God Eleoussa and St Nicholas in Nesebǎr were reconstructed during that period , as was the St Nicholas monastery near Pernik , according to a Hilandar monastery deed . In addition , the tsar also initiated the construction of the Dragalevci and Kilifarevo monasteries . Literary activity also flourished during the reign of Ivan Alexander . Several important literary works were created in the period , such as the Middle Bulgarian translation of the Manasses Chronicle ( 1344 – 1345 ) , currently preserved in the Vatican Secret Archives in Rome , the richly illustrated Tetraevangelia of Ivan Alexander ( 1355 – 1356 ) , now exhibited in the British Library , the Tomić Psalter ( 1360 ) , today in Moscow , and the Sofia Psalter ( 1337 ) . Ivan Alexander ' s rule was also marked by efforts to strengthen the position of the Bulgarian Orthodox Church by pursuing heretics and Jews . He organized two anti - heretical church councils , in 1350 and 1359 – 1360 , that condemned various sects such as the Bogomils , the Adamites and the Judaizers . The spiritual practice of hesychasm , a form of incantatory prayer , deeply influenced certain areas of the Eastern Orthodox world of the 14th century . A notable Bulgarian representative of the movement during Ivan Alexander ' s reign was Theodosius of Tǎrnovo . During this time , the Bulgarian Empire had trade relations with the Mediterranean maritime powers Venice , Genoa and Ragusa . In 1353 , Ivan Alexander issued a charter allowing Venetian merchants to buy and sell goods throughout Bulgaria after Doge Andrea Dandolo assured him they would observe the prior treaties between the two countries . In modern times , the rule of Ivan Alexander inspired Bulgarian national writer Ivan Vazov to write the novelette " Ivan - Aleksandǎr " and the drama " Kǎm propast " ( " Towards an Abyss " ) , in both of which the tsar is the main character . A piece of a garment signed by Ivan Alexander and interwoven with gold was discovered in a noble ' s grave near Pirot in the 1970s ; today it is preserved in the National Museum of Serbia in Belgrade . It is the first find of its kind , demonstrating a medieval tradition attested in writing according to which Orthodox rulers would present their most eminent dignitaries with a piece of a garment they had worn . Ivan Alexander Point on Nelson Island in the South Shetland Islands , Antarctica is named after Ivan Alexander of Bulgaria . Family . By his first wife Theodora of Wallachia ( nun Teofana ) , a daughter of Basarab of Wallachia , Ivan Alexander had several children , including Ivan Sracimir , who ruled as emperor of Bulgaria in Vidin 1356 – 1397 , associated emperors Michael Asen IV ( co - ruled c . 1332 – 1354 / 5 ) and Ivan Asen IV ( co - ruled 1337 – 1349 ) , and a daughter called Thamar ( Kera Tamara ) , who was married first to the " despotēs " Constantine ( Konstantin ) , and then to Sultan Murad I of the Ottoman Empire . By his second wife Sarah - Theodora , Ivan Alexander had several other children , which included Keraca Marija , who married the Byzantine Emperor Andronikos IV Palaiologos , Ivan Šišman , who succeeded as emperor of Bulgaria in Tǎrnovo 1371 – 1396 , Ivan Asen V , associated as emperor of Bulgaria by 1359 – 1388 ? , as well as two daughters named Desislava and Vasilisa .