Otherwise known as Philip the Magnanimous. Philip was the Landgrave of Hesse, in the Holy Roman Empire. He was a major supporter of the Lutheran movement and was a key figure in the reformation.
He did much work in attempting to unite the various protestant movements which led to the Marlburg Colloquy, 1529. However this was a failure and he did not manage to unite Luther and Zwingli.
In 1531 Philip formed the The League of Schmalkalden in an attempt to encourage protestant unity against Charles V, the Holy Roman Emperor.
However the scandal of Philip’s bigamy in 1540, which had been reluctantly sanctioned by both Martin Luther and Philip Melanchthon, destroyed his reputation. It also did much to damage to protestant cause. It was one of the factors which lead to Charles’ victory at the Battle of Muhlburg, 1547. Philip was captured in the battle and imprisoned, when he was released in 1552 he was a broken man.