THE SCARCITY OF historical sources prevents scholars from establishing irrefutable facts concerning the earliest past of the Slavic states in the Balkans. In this article I present a chronological survey of the key political stages in the development of late medieval Bosnia and its relationships, often military, with its closest neighbour, Croatia-Dalmatia (as the part of the composite Hungarian Kingdom— the Realm of St. Stephen). I have defined the following major phases in this history of Bosnian-Croatian relations in the late Middle Ages: Croatian rule of Bosnia under the Šubić family, 1301 to 1322; high aspirations of the Bosnians under the reign of Stjepan (Stephen) II, 1322 to 1353; setbacks in the west of Bosnia, albeit temporary, in the period of Ban Tvrtko, 1353 to 1377; an expansionary period under kings Tvrtko I and Dabiša, 1377 to 1395; a period of turmoil under Hrvoje Vukčić, 1398 to 1416; followed by what I call the era of permeable border between Bosnia and Croatia-Dalmatia, when Venice and the Ottoman Turks emerged as the key players of the region in the period to 1444; and, finally, the fall of medieval Bosnia following constant Turkish pressure from 1444 to 1463. Many effects from this period have major repercussions on the shaping of the political landscape of the Balkans through to this very day.

The first written record, which is widely considered to be trustworthy, is De administrando imperio (‘On the Governance of the Empire’), a domestic and foreign policy manual compiled for Romanos, son of Emperor Constantine VII Porphyrogenitus (r. 913– 959). According to this record, in the early tenth century the western Balkan area was divided into several political entities ruled by South Slavs, the largest of them being Serbia and Croatia. They bordered each other along a line which generally followed the Vrbas River.

At that time, Bosnia, situated on the upper and middle course of the Bosna River, existed as a horion (“small land”) within the political borders of Serbia.2 After the gradual disintegration of this large Serbian state, Bosnia developed or re-developed its home rule.3 By the mid-twelfth century, if not earlier, it was a fully independent state, although at times it succumbed to the influence of powerful neighbouring states— primarily Byzantium (until the 1180s) and Hungary (throughout the Middle Ages).