Ban Kulin

In 1183, Kulin Ban led his troops with the forces of the Kingdom of Hungary under King Béla and the Serbs under Stefan Nemanja, who had just launched an attack on the Byzantine Empire. The cause of the war was Hungary's non-recognition of the new emperor, Andronikos Komnenos. The united forces met little resistance in the eastern Serbian lands – the Byzantine squadrons were fighting among themselves as the local Byzantine commanders Alexios Brannes supported the new Emperor, while Andronikos Lapardes opposed him – and deserted the Imperial Army, going onto adventures on his own. Without difficulties, the Byzantines were pushed out of the Morava Valley and the allied forces breached all the way to Sofia, raiding Belgrade, Braničevo, Ravno, Niš and Sofia itself.

In 1199, Serbian prince Vukan Nemanjić informed the Pope, Innocent, of heresy in Bosnia. Vukan claimed that Kulin, a heretic, had welcomed the heretics whom Bernard of Split had banished, and treated them as Christians. In 1200, the Pope wrote a letter to Kulin's suzerain, the Hungarian King Emeric, warning him that "no small number of Patarenes" had gone from Split and Trogir to Ban Kulin where they were warmly welcomed, and told him to "Go and ascertain the truth of these reports and if Kulin is unwilling to recant, drive him from your lands and confiscate his property". Kulin replied to the Pope that he did not regard the immigrants as heretics, but as Catholics, and that he was sending a few of them to Rome for examination, and also invited that a Papal representative be sent to investigate. Unconvinced, the Pope sent his legates to Bosnia to interrogate Kulin and his subjects about religion and life, and if indeed heretical, correct the situation through a prepared constitution. The Pope wrote to Bernard in 1202 that "a multitude of people in Bosnia are suspected of the damnable heresy of the Cathars." The two legates sent by the Pope went through the country of Bosnia and interrogated the clergy.

Not only did Casamaris listen to his informants' answers, but where they were in error, he would have taught them correct doctrine, in line with Innocent's directive. John must have convinced himself that he had fulfilled Innocent's command to correct the krstjani, because the "Confessio" (Abjuration) signed at Bilino Polje by seven priors of the Krstjani church on 8 April 1203, makes no mention of errors. The same document was brought to Budapest, 30 April by Casamaris and Kulin and two abbots, where it was examined by the Hungarian King and the high clergy. Kulin's son.[10][11]

Copy B of the Charter of Ban Kulin.

The Charter of Ban Kulin was a trade agreement between Bosnia and the Republic of Ragusa that effectively regulated Ragusan trade rights in Bosnia written on 29 August 1189. It is one of the oldest written state documents in the Balkans and is among the oldest historical documents written in Bosančica. The charter is of great significance in national pride and historical heritage.[12][13]

After his death in 1204, Ban Kulin was succeeded to the Bosnian throne by Stjepan, ban of Bosnia, often deemed his son.[14]