He was at first supportive of reconciliation of Orthodox with Catholic theology, but later returned to Greek Orthodoxy and wrote against both Catholicism and Calvinism. Leaving Rome, he went to Constantinople, and later (1646) to Târgoviște in Wallachia where he established (or revived) a Greek school. In 1651 he travelled to Palestine in the company of patriarch Paisius of Jerusalem, taking monastic vows and adopting the monastic name of Paisius.