Answer based on context:

The Münster rebellion was an attempt by radical Anabaptists to establish a communal sectarian government in the German city of Münster. The city was under Anabaptist rule from February 1534, when the city hall was seized and Bernhard Knipperdolling installed as mayor, until its fall in June 1535. It was Melchior Hoffman, who initiated adult baptism in Strasbourg in 1530, and his line of eschatological Anabaptism, that helped lay the foundations for the events of 1534-1535 in Münster.

How many years after Melchior Hoffman initiated adult baptism in Strasbourg was Münster under Anabaptist rule?
4