Institutes of the Christian Religion

Calvin published the first edition of this work in 1536, at age twenty-six, as a defense of the evangelical faith addressed to King Francis I of France. He expanded it over nearly twenty-five years into the definitive 1559 edition, organized into four books that follow the structure of the Apostles' Creed.

Alongside the works of Augustine and Aquinas, it stands as one of the most influential theological summas in the history of the Western church, and the literary foundation of the entire Reformed tradition that followed.