 After that, he lectured in ecumenical theology at the Vrhbosna Theology Seminary in Sarajevo from 1974 until 2004 (with breaks).On 7 December 1979, Perić was named rector of the Pontifical Croatian College of St. Jerome in Rome.He later lectured on ecumenical theology at the Pontifical Gregorian University in Rome from 1989 until 1992, and also on eastern theology at the Faculty of Catholic Theology in Zagreb from 1991 until 1992.