Major events of 1531 AD include: * September: Philipp Melanchthon writes, and Martin Luther revises, the Apology of the Augsburg Confession. * November 9: Martin Luther. Jr, fourth child of Martin Luther, born * Lutheran princes create the Schmalkaldic League, which goes to war with the Holy Roman Empire under Charles V. Martin Luther's Warnung an die lieben Deutschen openly advocates resistance in a righteous cause. * Sir Thomas Moore refers to religious adversaries as "Evaungelicalles," possibly the first reference to Evangelicalism. * Debates begin between Protestants and Catholics over the nature of the Eucharist