Philipp Melanchthon, who received his Greek last name--a translation of his real name, Schwartzerd (Black Earth)from his early mentor and distant relative Johann Reuchlin, is now chiefly known as one of the German Reformers, a close associate of Martin Luther. He was honored during Luther's lifetime, but after Luther's death he was attacked for allegedly altering some of Luther's theological doctrines. In the nineteenth century his reputation as a humanist teacher was established by Karl Hartfelder, who called him "Praeceptor Germaniae" (the Teacher of Germany). Modern church historians have called Melanchthon "the man who helped Luther discover the gospel."

Unlike Luther, Melanchthon published little in German--he wrote mostly for students and scholars, whose universal language was Latin--but many of his works were translated into German by others (not always with his knowledge). Although he is now best known as a Reformer, from the beginning of his career...