Archdiocese

After the death of the last Trpimirović, Hungarian King Ladisalus Arpad in 1091A.D., citing his ‘legitimate right’as brother of Jelena - Lepa (Beautiful Jelena), widow of King Zvonimir, annexed Pannonian Croatia and decided his nephew Almoš would govern it.

He took one step further and separated Pannonian Croatia from the jurisdiction of the Metropolitan See of Split and the rest of Croatia, so he established the Diocese of Zagreb around 1094 A.D., or as historical sources state between the second half of 1093 A.D. and the first half of 1095 A.D.

The main reason the Diocese in Zagreb was established was that northern Croatia was far from the episcopal seats in Split, Knin and Nin so the local Christians could easily go astray to heresy.  It was for a religious reason and was fully justified.

Another reason was to strengthen the position of the Arpad dynasty in Croatia. The Diocese of Zagreb was under the jurisdiction of the Metropolitan See of Ostrogon until 1180 A.D., when it fell under the jurisdiction of the Archdiocese of Kalocha. In 1852 the Diocese of Zagreb was separated from it and elevated to the level of an Archdiocese and Metropolitan See of Croatia and Slavonia. 

Pope Urban II (1088 A.D. -1099A.D.), as protector of the Croatian kingdom, did not approve Ladislus' policy towards Croatia so Ladislaus decided to get the approval for establishing the Diocese of Zagreb from the antipope Clement III (Wibert Ravenna).

After the end of the Avignon papacy, the Diocese was not abolished as the Pope did not oppose its existence.

In 1227 A.D. Pope Gregory IX granted deeds of gift and privileges of the Diocese of Zagreb, including the Felitianus’ Charter from 1134 A.D., the oldest preserved document of Croatian land between the rivers Sava and Drava. It is not known whether Ladislaus’ Charter on the establishment of the diocese exists. After his death people in Hungary venerated him as a saint, without him being actually canonized. The Holy See subsequently canonized him and accepted the existence of the Diocese of Zagreb.

Ladislaus’ political and military work in Croatia soon collapsed, and Duke Almoš had to leave Croatia in 1095A.D. The only thing left from his rule over Croatia was the Diocese of Zagreb which had all reasons for its survival.

But the Arpad family returned to the Croatian throne six years later when Croatia entered into a personal union with Hungary, which meant that the two kingdoms were united under the rule of the same king. The Hungarian king Coloman Arpad was crowned as King of Croatia in 1102 A.D. in Biograd. Thus, the Diocese of Zagreb remained under the sponsorship of the King of Croatia and Hungary.