Philip the Magnanimous (1504-67), landgrave of Hesse; German prince who helped ensure the survival of Protestantism in the early years of the Reformation. Philip became a Lutheran in 1524; two years later, he and other Lutheran princes formed the League of Torgau to protect themselves against a coalition of German states loyal to Roman Catholicism. In 1529 he sponsored the Colloquy of Marburg, a conference that tried unsuccessfully to unite the Protestants of Germany and Switzerland. Philip was one of the principal organizers of the Schmalkaldic League (1531), which opposed efforts by Holy Roman Emperor Charles V to eradicate Lutheranism. Defeated by Charles in 1547, he remained the latter's prisoner until 1552. Philip's efforts were rewarded in 1555, when Lutherans were granted equality with Roman Catholics in Germany.