Constantine Dragaš Konstantin Dejanović ( ) , also known as Constantine Dragaš ( Константин Драгаш ; 1365 - 1395 ) was a Serbian magnate that ruled a large province in eastern Macedonia under Ottoman suzerainty , during the fall of the Serbian Empire . He succeeded his older brother Jovan Dragaš , who had been an Ottoman vassal since the Battle of Maritsa ( 1371 ) which had devastated part of the Serbian nobility . The brothers had their own government and minted coins according to the Nemanjić style . His daughter Jelena married Byzantine Emperor Manuel II Palaiologos in 1392 . He fell at Rovine ( May 17 , 1395 ) , serving the Ottomans against Wallachia , fighting alongside Serbian magnates Stefan Lazarević and Marko Mrnjavčević . Constantine ' s grandson , last Byzantine Emperor Constantine XI , was named after him , and even used the name " Dragaš " . Life . Early . Constantine ' s father was the " despot " and " sevastokrator " Dejan , who had held the Kumanovo - region under the rule of Stefan Dušan ( r . 1331 - 1355 ) . Constantine ' s mother Teodora Nemanjić was a half - sister of Dušan . His maternal grandparents were King Stefan Dečanski ( r . 1321 - 1331 ) and Queen Maria Palaiologina . Reign . In ca . 1365 , his older brother Jovan Dragaš was holding Štip and Strumica . Jovan was elevated to " despot " by Emperor Uroš V ( before 1373 ) , as Emperor Dušan had elevated Dejan , their father . Ottoman sources report that in 1373 , the Ottoman army compelled " Saruyar " ( Jovan Dragaš ) in the upper Struma , to recognize Ottoman vassalship . Constantine had helped Jovan in ruling the lands , and when Jovan died in 1378 / 1379 , Constantine succeeded , subsequently managing to govern large portions of northeastern Macedonia and the Struma valley . He minted coins , as had his brother done . The Dragaš family generously donated to several monasteries on Mount Athos , including Hilandar , Pantaleimon ( Rossikon ) and Vatopédi . On the 10th of February 1392 , his daughter Jelena married Manuel II Palaiologos , and the next day , they were crowned Emperor and Empress by the patriarch . After the battle of Maritsa , they were forced to become vassals of the Ottoman Empire , but they maintained close links with their Christian neighbors , including the Byzantine Empire . In 1395 , together with his neighbor and ally , the Serbian king of Prilep Marko , Constantine Dragaš was killed fighting for their Ottoman overlord Sultan Bayezid I against Mircea cel Bătrân of Wallachia at Rovine , near Craiova . The Ottomans named Constantine ' s capital Velbažd / Velbužd after him , " Köstendil " ( now Bulgarian Kyustendil ) . Family . Constantine Dragaš was married twice . The name of his first wife is unknown , but she is not identical with Thamar ( Tamara ) , the daughter of the Emperor ( tsar ) Ivan Alexander of Bulgaria , who had married a certain " despotēs " Constantine . Constantine Dragaš married as his second wife Eudokia of Trebizond , daughter of Emperor Alexios III of Trebizond and Theodora Kantakouzene . By his first wife , Constantine Dragaš had at least one daughter and possibly a son : Legacy . He is venerated in Serb epic poetry as Beg Kostadin ( in poetry he was given a title of beg because he became an Ottoman vassal ) . Notes .