 While Križanić had a strong desire to travel to Moscow with the ambitious goal of uniting the Roman Catholic and Russian Orthodox churches, he was assigned missionary duties in Zagreb, where he was a teacher at the Zagreb Theological Seminary as well as a priest in several neighboring towns.Križanić managed to secure permission from the papacy for a brief visit to Moscow from 25 October to 19 December 1647. as part of a Polish embassy.However, he was not able to secure permission for a prolonged stay until 1658 (it was retracted shortly after being issued, a fact that Križanić simply ignored) and he did not arrive in Moscow until 17 September 1659.