Institutes of the Christian Religion is a seminal work on Protestant systematic theology by John Calvin. First published in Latin in 1536 and in French in 1541, it was intended as an introductory textbook on the Protestant faith for those with some learning already. The book covers a broad range of theological topics, from the doctrines of church and sacraments to justification by faith alone and Christian liberty. It also vigorously attacks the teachings of those Calvin considered unorthodox, particularly Roman Catholicism. The over-arching theme of the book is the idea of God's total sovereignty, particularly in salvation and election. The Institutes are a primary reference for the system of doctrine adopted by the Reformed churches, usually called Calvinism.