Leo X, pope from 1513-1521. The one that excommunicated Luther. From a portrait by Raphael.
The 16th Century humanist scholar, Erasmus of Rotterdam (1469-1536). He produced the first critical edition of the Greek New Testament, which Luther used in his teaching and Bible translation. Later he was Luther's opponent in the controversy over the place of the human will in salvation. It was against Erasmus' "Free Will" that Luther wrote his masterpiece, "Bondage of the Will" in 1525. (From a painting by Hans Holbein the Younger).
Johann von Staupitz (1469-1524), Vicar General of the order of Augustinian Hermits. He was Luther's superior while the reformer was a monk both in Erfurt and Wittenberg. It was Staupitz that encouraged Luther to get his doctorate, and recommended Luther for the chair of Biblical studies at the University of Witttenberg.
The three electors of Saxony that protected Martin Luther during the critical years of the Reformation: (from left to right) Frederick the Wise (elector from 1486-1525), John the Steadfast (brother of Frederick, elector from 1525-1532), John Frederick (son of John the Steadfast, elector from 1532-1547).