The Formicarus (1435) gives the earliest if not the most complete description of what happens. Supplied with friends who have already forsworn God, the applicant arrives at a church on a Sunday morning very early and renounces God and the One, Holy, and Apostolic Church. He pays homage to the devil, drinks the blood of sacrificed children, and subscribes to the rules of the damned, which cover many things from diet to cursing and sacrificing. He expresses the desire to trade his soul for one or more favors from The Evil One, often wealth or power for a specified number of years.
Another way of selling your soul to the Devil was to do the following:
1. Get a piece of virgin parchment (from the first calf a cow bears, not a piece never written on before).
2. Write on it with your own blood: "I promise GREAT DEMON to repay him in seven years for all he shall give me. In witness whereof, I sign my name."
3. Sign it in your own blood.
4. Then, within a magic circle, hold the document in you hand and recite the invocation:
LUCIFER, Emperor, Master of All Rebellious Spirits, I beseech thee to be favorable to me in calling upon thy GREAT MINISTER which I make, desiring to make a pact with him.
BEELZEBUB, Prince, I pray thee also, to protect me in my undertaking.
ASTAROTH, Count, be propitious to me and cause that this night the GREAT DEMON appear to me in human form and without any evil smell, and that he grant me, by means of the pact which I shall deliver to him, all the treasures of which I have need.
GREAT DEMON, I beseech thee, leave thy dwelling, in whatever part of the world you may be, to come speak with me; if not, I shall thereto compel thee by the power of the might words of the Great Key of Solomon, whereof he made use to force the rebellious spirits to accept his pact.
Appear then instantly or I shall continually torment thee with the might words of the Key: AGLON, TETRAGRAMMATON, VAYCHEON, STIMULAMATHON, EROHARES, RETRASAMATHON, CLYORAN, ICION, ESITION, EXISTIEN, ERYONA, ONERA, ERASYN, MOYN, MEFFIAS, SOTER, EMMANUEL, SABAOTH, ADONAI. I call you. AMEN.
When the demon appears, throw him the pact. Do not step outside the circle on any account.