Tvrtko I of Bosnia

Stephen Tvrtko I (Serbo-Croatian:Stjepan Tvrtko, Стефан Твртко; 1338 – 10 March 1391) was the first King of Bosnia. A member of the House of Kotromanić, Tvrtko succeeded his uncle Stephen II as Ban of Bosnia in 1353. After initial difficulties – the loss of large parts of Bosnia to his overlord, King Louis I of Hungary, and brief deposition by magnates – Tvrtko's power grew considerably. He conquered the remnants of the neighbouring Serbian Empire in 1373, and in 1377 he had himself crowned King of Bosnia and Serbia. The expansion of the Kingdom of Bosnia continued, with Tvrtko gaining control of the entire Pomorje. The death of King Louis and accession of Queen Mary in 1382 allowed Tvrtko to take advantage of the ensuing succession crisis in Hungary. After bitter fighting from 1385 to 1390, Tvrtko succeeded in conquering large parts of Slavonia, Dalmatia and Croatia proper. Following the Battle of Kosovo in 1389, however, his tenuous claim to Serbia became a mere fiction. His death in 1391 prevented him from solidifying the Kotromanić hold on Slavonia, Dalmatia and Croatia. Tvrtko extended medieval Bosnia's borders to their farthest limits, and is widely considered one of his country's greatest medieval rulers.