December 20, 1552: Former nun Katherine von Bora, Martin Luther's wife from 1525 to Luther's death in 1546, dies (see issue 39: Luther's Later Years).
December 20, 1560: The Scottish Reformed Church, organized with the help of John Knox, holds its first assmbly (see issue 46: John Knox).
December 20, 1576: Edmund Grindal, Archbishop of Canterbury, sends a letter to Queen Elizabeth protesting her order that he tell preachers throughout England to stop speaking so often. She felt three or four sermons per year were sufficient. Grindal's refusal to enforce her wishes earned him house arrest.
December 20, 1787: The Shakers, a millenarian communal society in New Lebanon, Indiana, experience a revival. The religious fervor continued throughout the frontier, crossing denominational barriers.