Petar of Serbia

Petar Gojnikovi or Peter of Serbia was Prince of the Serbs from 892 to 917. He ruled and expanded the First Serbian Principality , and won several wars against other family members that sought the crown. He was the first Serbian monarch with a Christian name.

Petar was born between 870 and 874, as the son of the Prince Gojnik, the youngest son of dynastic founding father Vlastimir. His Byzantine Christian name, in relation to the previous generation of pagan names, shows the spread Christianization among the Serbs. At the time of his birth, Serbia was ruled as an Oligarchy of the three brothers Mutimir, Gojnik and Strojimir, although Mutimir, the oldest, had supreme rule.

Source: Wikipedia