Croats of Bosnia and Herzegovina Dalmatian Croatia formed a united Croatian kingdom, which included Dalmatia and part of Bosnia and Herzegovina, Pannonia (eastern Slavonia and northeastern Bosnia), and Savia (western Slavonia). In 1102 Croatia entered into a union with the Kingdom of Hungary. After this, Bosnia, which was earlier part of the Kingdom of Croatia, started to disassociate with Croatia. At first, Bosnia became a separate principality under Ban Kulin who managed to solidify Bosnian autonomy at the expense of more powerful neighbours, but only in the 14th century did Bosnia become a formidable state. In the 14th century, King Tvrtko I conquered part of
Serbs of Bosnia and Herzegovina Bosnia and Herzegovina, large parts of modern-day Croatia and parts of modern-day Serbia and Montenegro, with Tvrtko Ieventually establishing the Kingdom of Bosnia in 1377. The Kotromanić intermarried with several southeastern and central European royal houses. The last sovereign, Stephen Tomašević, ruled briefly as Despot of Serbia in 1459 and as King of Bosnia between 1461-63, before losing both countries – and his head – to the Ottoman Turks. The Battle of Bileća was fought in August 1388 between the forces of the Kingdom of Bosnia led by Duke (Voevoda) Vlatko Vuković and the Ottoman Turks under the leadership of