"Beloved son! continue to defend the Catholic Faith; God, for whom you fight, will not abandon His cause. He will, I am confident, grant success against the Turks and the other unbelievers to you and the rest of the Christians with great glory and honour."

“I, Pope Calixtus, vow to Almighty God and the Holy Trinity that by war, maledictions, interdicts, excommunications, and all other means in my power, I will pursue the Turks, the most cruel foes of the Christian name.”

“I have been chosen for the destruction of the enemies of the Faith.”

“Away, away with these things! take them for the Turks! Earthenware will do quite as well for me!”

“The Christian who does not now render assistance in following up the victory God has granted proves himself unworthy of divine favours.”

“We ratify the law, but we condemn your interpretation, for He of whom ye say that He will come—our Lord Jesus Christ—has come, as the Church teaches us and preaches.”

“I, Pope Calixtus III, promise and vow to the Holy Trinity, Father, Son, and Holy Ghost, to the Ever-Virgin Mother of God, to the Holy Apostles Peter and Paul, and to all the heavenly host, that I will do everything in my power, even, if need be, with the sacrifice of my life, aided by the counsel of my worthy brethren, to reconquer Constantinople, which in punishment for the sin of man has been taken and ruined by Mahomet II, the son of the devil and the enemy of our Crucified Redeemer. Further, I vow to deliver the Christians languishing in slavery, to exalt the true Faith and to extirpate the diabolical sect of the reprobate and faithless Mahomet in the East. For there the light of Faith is almost completely extinguished. If I forget thee, O Jerusalem, let my right hand be forgotten. Let my tongue cleave to my jaws, if I do not remember thee. If I make not Jerusalem the beginning of my joy, God and His holy Gospel help me. Amen.”