January 21, 1525: Conrad Grebel (Ulrich Zwingli's former protege) rebaptizes George Blaurock, a former monk, in a secret, illegal meeting of six men in Zurich. This meeting is now considered the birth of the Anabaptist movement (see issue 5: Anabaptists).

January 21, 1549: In the first of four Acts of Uniformity, the English Parliament requires all Anglican public services to exclusively use of The Book of Common Prayer.

January 21, 1621: Pilgrims leave the Mayflower and gather on shore at Plymouth, ...