Ban Tvrtko I from the Kotromanic dynasty was crowned on October 26, 1377, and thus was established the independent Kingdom of Bosnia.
Tvrtko was crowned as the king of Bosnia in the settlement Mile near Visoko (today’s Arnautovici), which was the place for the crowning of all Bosnian kings that came later as well. After the death of the Hungarian king in 1382, there were riots in the area of the Dalmatian coast, and King Tvrtko decided to use this opportunity to send the Bosnian army to that part of Dalmatia and take full control over Dalmatia together with the islands. In that way, he managed to affiliate Split, Trogir, Sibenik, and the islands of Brac, Korcula, and Hvar to Bosnia.
In the last decade of his reign, King Tvrtko faced with invasions of Ottomans in Bosnia, first in autumn of 1386, and then in summer of 1388 at Bileca, when Bosniaks led by prince Vlatko Vukovic won in the battle against the Ottomans. Bosniaks returned from the battle in Kosovo without dramatic losses, as reported by Historija.ba.
After Tvrtko’s death in 1391, the unstable political climate re-emerged in Bosnia, and it was caused by the Hungarian-Byzantine rivalry which caused alienation among Bosnian nobility once again. This resulted in a frequent change of Bosnian kings, and Hungary also tried to take advantage of its pretensions on Bosnia.
(Source: faktor.ba)