John Albert I, duke of Mecklenburg (d. 1576)
John Albert I, Duke of Mecklenburg, in older literature known as John or Johann (23 December 1525 – 12 February 1576), was the reigning Duke of Mecklenburg-Güstrow from 1547 to 1556 and of Mecklenburg-Schwerin from 1556 to 1576. In 1549 John Albert I saw to it that the parliament of Mecklenburg carried through the Reformation for the entire Duchy.