Tvrtko I of Bosnia

Tvrtko inherited the ban of Bosnia in 1353 as a boy, his mother serving as regent after his father's brief term. Early rule brought humiliation - he lost territory to Hungary's Louis I and was briefly deposed by his own magnates - but he recovered. In 1373 he seized pieces of the collapsing Serbian Empire after the death of Uroš the Weak, then in 1377 crowned himself king of Bosnia and Serbia, claiming descent from the extinct Nemanjić line. He pushed west to the Adriatic, taking the Primorje coast and its port cities, building a navy and new settlements. Louis's death in 1382 opened Hungary and Croatia to bitter warfare; by 1390 Tvrtko controlled large stretches of Dalmatia and Croatia proper. His Serbian claim evaporated after Kosovo in 1389, when the rulers he meant to subdue became Ottoman vassals, though his own forces repelled the Turks' first Bosnian raids. He died suddenly in March 1391, leaving his son Tvrtko II but a throne that passed to Dabiša, under whom the enlarged kingdom began to unravel.