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
Bosnia and Herzegovina Bosnia and Herzegovina Bosnia and Herzegovina ( or ; abbreviated B&H; Bosnian and Serbian: "Bosna i Hercegovina" (BiH) / Боснa и Херцеговина (БиХ), Croatian: "Bosna i Hercegovina" (BiH), ), sometimes called Bosnia–Herzegovina, and often known informally as Bosnia, is a country in Southeastern Europe in the Balkan Peninsula. Sarajevo is the capital and largest city. Bosnia and Herzegovina is an almost landlocked country – it has a narrow coast at the Adriatic Sea, about long surrounding the town of Neum. It is bordered by Croatia to the north, west and south; Serbia to the east; and Montenegro to the southeast,