A Fourth Book of Occult Philosophy (c. 1565) spuriously attributed to Agrippa gives detailed instructions as to how pentacles should be formulated:
But we now come to speak of the holy and sacred Pentacles and Sigils. Now these pentacles, are as it were certain holy signes preserving us from evil chances and events, and helping and assisting us to binde, exterminate, and drive away evil spirits, and alluring the good spirits, and reconciling them unto us. And these pentacles do consist either of Characters of the good spirits of the superiour order, or of sacred pictures of holy letters or revelations, with apt and fit versicles, which are composed either of Geometrical figures and holy names of God, according to the course and maner of many of them; or they are compounded of all of them, or very many of them mixt.