Josif Rajačić’s family moved to the north-western part of the Lika region at the end of 17th century, when Prince Rajak led many people from Banjaluka to the area between Brinje, Otočac and Senj in Lika. After two years of studying philosophy with the Piarists (a Catholic educational order) in Hungary’s Szeged, Rajačić travelled to Vienna to study Latin, arts and higher learning. When the French, who were then at war with Austria, came close to Vienna in 1809, Rajačić joined the students’ battalion. At the invitation of the Orthodox Bishop of Banjaluka Mojsije Mioković, he soon entered a monastic order and became the Archimandrite of the Gomirje monastery. In 1829, he was appointed Episcope of the Dalmatia Eparchy. Immediately upon his arrival in Šibenik, Rajačić established a clerical school and opened a similar one in Dubrovnik soon after.

By a Court Chancellor’s decision, he became the Episcope of Vršac in 1833 and after death of Stefan Stanković in 1842, the Austrian Emperor appointed him Metropolitan of Karlovac. Rajačić gained prominence at that time thanks to an important speech at the Upper House of the Požun Sabor (parliament). In that speech, he emphasised that Serb people, regardless of all the privileges granted them by emperors Leopold II, Joseph I, Charles VI and Maria Theresa, remained in a subordinated position.

Related to revolutionary movements in 1848, Rajačić called a people’s assembly – the so-called May Assembly in May of that, where participants elected him Patriarch and Stevan Šupljikac of the Ogulin regiment Duke. The following conclusions were reached at the May Assembly:

  1. Serb people are “politically free and independent under the House of Austria and the general Hungarian Crown”
  2. The Serb Duchy is declared encompassing “Srem with the Frontier, Baranja, Bačka with the Bečej district and the Šajkaš Battalion, Banat with the Frontier and the Kikinda District”
  3. The Serb Duchy enters into a “political alliance… based on freedom and complete equality” with the Triune Kingdom of Croatia, Slavonia and Dalmatia
  4. A Permanent People’s Committee is established as an executive body of the People’s Sabor (Assembly) and its members are appointed
  5. The “Vlach people’s independence” is recognised
  6. A committee is designated to present the Assembly’s conclusions to the ruler and the Croatian Sabor
  7. A decision to send a special delegation to the Slavonic Congress in Prague is taken

Although a vast majority of Serbs in the first flush of rapture accepted conclusions of the May Assembly, there were still some who considered them dangerous. A democratic current in Croatia, primarily the intellectuals and youth in Zagreb, sincerely welcomed an alliance with Vojvodina Serbs and accepted the May Assembly’s decisions, while those more conservative shunned the alliance. Emperor Ferdinand and the Hungarian government did not recognize demands of the May Assembly. The Austrian emperor repaid the Serbs for their participation in the war against Hungarians only later, in 1849, by establishing the Serbian Voivodeship and Banat of Temeschwar (a dutchy) which also encompassed two Syrmia districts – Ilok and Ruma.

During a counterrevolution at the time of Bach’s Absolutism (1849 — 1860), Rajačić stood firmly by the Austrian authorities. He took it hard when the Serbian Voivodeship was abolished in 1860, and sent a note of protest to the emperor. In a letter written in his own hand, the emperor approved holding a Church-National Assembly, which opened on 2 April 1861 (the so-called Annunciation Assembly). This assembly’s task was to present conditions under which it would agree to an annexation the previously abolished Serbian Voivodeship and Banat of Temeschwar to the Kingdom of Hungary. Patriarch Rajačić died on 1 December that same year, 1861, and was buried in the Karlovac Cathedral.