April 26, 1521: After Charles V promises to take firmer measures against his doctrines, Luther leaves the Diet of Worms. A month later, his teachings are formally condemned (see issue 34: Luther's Early Years).
April 26, 1877: Residents of Minnesota observe a state-wide day of prayer, asking deliverance from a plague of grasshoppers that had ruined thousands of acres of crops. The plague ended during that summer.
April 26, 1992: Worshipers celebrate the first Russian Orthodox Easter in Moscow in 74 years.
April 21, 1109: Anselm, archbishop of Canterbury and one of the most profound thinkers of the Middle Ages, dies around age 76. He attained fame for his argument that faith is the precondition of knowledge ("credo ut intelligam"), his "satisfaction theory" of the atonement ("No one but one who is God-man can make the satisfaction by which man is saved") and for his ontological argument for God's existence.
April 21, 1142: Medieval French philosopher, teacher, and theologian Pierre Abelard dies. Though ...