A native of Split in present-day Croatia, Vocatius was appointed the bishop of Duvno in the Ottoman Bosnia and Herzegovina in 1551, on the request of the local populace.
[1] Friar Marijan Žugaj thinks that he might be a member of the Vukčić-Hrvatinić family or a grandson of Stjepan Vukčić Kosača.
[1][6] Having encountered difficulties in his diocese, In September 1553, Vocatius went to Naples, where the Franciscan provincial Angelus Aversani wrote a recommendation to King Ferdinand I to transfer him somewhere else if necessary.
Pope Paul IV personally ordered an investigation into accusations against Vocatius for his alleged double standard towards the Ottomans and his animosity towards the Franciscans.
[2] During Vocatius' pastoral visit to the Catholics in Herzegovina in 1563, the Ottoman authorities chased him down, so he hid in Mostar and Ljubuški.
In 1575, because of a long absence from his dioceses, the papal advisor Giulio Antonio Santorio reprimanded him to Pope Gregory XIII.
However, thanks to the good connections he had with Philip II's father, King Charles V and some members of the Roman Curia, Vocatius managed to secure his transfer to the vacant Diocese of Muro Lucano in the Southern Italian region of Basilicata, where he was appointed the bishop on 9 May 1575.