Petar Kočić was born into a Bosnian Serb family on 29 June 1877 in the hamlet of Stričići, in the Zmijanje region, near Banja Luka in northern Bosnia. His father, Jovan, was an Eastern Orthodox priest and his mother, Mara, was a housewife. Within a year of his birth, the Bosnia Vilayet was occupied by Austria-Hungary, bringing more than four centuries of Ottoman rule to a sudden end. Kočić's father had taken his priestly vows in 1873. In 1879, Kočić's mother died while giving birth to his younger brother Ilija, and his father decided to become a monk at the Gomionica Monastery, where he adopted the monastic name Gerasim.