Philipp Melanchton: Letter to Erasmus (1524).

"Philip Melanchthon (1497-1560) was a German Lutheran reformer, collaborator with Martin Luther, the first systematic theologian of the Protestant Reformation, an intellectual leader of the Lutheran Reformation, and influential designer of educational systems. He stands next to Luther and John Calvin as a reformer, theologian, and shaper of Protestantism."
Text: archive.org/de...