In these 5 letters, Frederick the Great compliments Voltaire on his genius, and discusses topics common throughout many of his letters, including such topics as freedom of religion and of opinion, theology, superstitions, the Vatican, and the philosophers. Three of the letters in this folder include a poem in the body of the letters. The poems appear to be written by Frederick.

The letter dated May 24, 1770 contains an interesting line which may be a genuine compliment or a sarcastic criticism of the Catholic Church, it is difficult to tell. "Among all the saints of the Church, I don't know anyone who is comparable, and I will begin by saying, Saint Voltaire, pray for us."

Each letter is signed by Frederick.