On 18 December 1858, Buconjić passed the professor exam in Bologne, where he discussed natural law and was awarded the highest grades. When Trionfetti saw his grades, he invited Buconjić to Rome to lecture at Antonianum, where Buconjić was appointed professor on 8 June 1860. While lecturing in Rome, Buconjić connected with the members of the Pontifical Croatian College of St. Jerome, then a student at the Collegium Germanicum et Hungaricum Josip Stadler, who would become his good friend (and who later become the archbishop of Vrhbosna) as well as Cardinal Alessandro Barnabò, the Prefect of the Propaganda, which would influence his later life and help him become a bishop. Buconjić also befriended the Croatian nationalist revolutionary Eugen Kvaternik, and was influenced by his ideas, which he discussed with Stadler. His other Roman friends included Franjo Rački and Menci Clement Crnčić. Buconjić's lecturing drafts during his tenure were not preserved but the speech he gave before the Pontifical Croatian College of St. Jerome was published under the title "Speech on the Occasion of the Millennial Celebration of the SS Slavic Apostles Cyril and Methodius" in 1863. Apostolic Vicar of Herzegovina Rafael Barišić died on 14 August 1863, and many saw the young Buconjić as his successor. However, Buconjić rejected such a possibility. After Bosnian Franciscans tried to take the vacant position for one of their own, and thus reclaim the Herzegovinian Custody, Buconjić acted to prevent them. He visited Pope Pius IX at his residence in Castel Gandolfo and asked him to appoint a Herzegovinian Franciscan as the apostolic vicar. The Pope conceded and appointed Kraljević the titular bishop of Motella and apostolic vicar of Herzegovina. Custos of the Franciscan Custody of Herzegovina After several requests to return to Herzegovina, Buconjić's appeals were accepted. He lectured in Rome until 20 December 1866, when he returned to the Franciscan friary in Široki Brijeg to teach dogma and morals. In 1871 he gained the highest Franciscan academic title of jubilee lecturer. The Custody's administration decided already in 1865 to establish new parishes, including the one in Buconjić's home village Drinovci. Buconjić helped them to find a lot for the construction of a new parochial residence. In 1871 Drinovci became at first a chaplaincy, while Buconjić was named its chaplain, and in 1873 it was elevated to the status of a parish, with Buconjić as its first parish priest. While in Drinovci, Buconjić