The Astrologer’s Oath in Antiquity

When Orpheus initiated strangers into his mysteries, he required nothing of them but an oath — an oath backed by the fearful authority of religion — that the rites once learned would not be betrayed to profane ears. It is generally agreed that Plato also was concerned that the cherished concepts of his secret discourses should not be revealed to the untaught. Pythagoras, too, and our Porphyry believed that their ideas should be enshrouded in religious silence.

Therefore, following the rule of these men, my dear Mavortius, I beg you to take an oath by God, the Creator of the Universe, who has made and regulated everything under the control of everlasting Necessity, who has shaped the Sun and Moon, who arranged the order and courses of all the stars, who collected the waves of the sea between boundaries of land, who forever kindles the encircling divinity of the heavens, who maintains the earth balanced evenly in the middle of the universe, who has created with his majestic divine skill all men, beasts, birds, and every manner of living thing, who moistens the earth with ever-flowing fountains, who makes constant and ever-changing the breath of the winds, who has created all things out of the four contrasting elements, who initiated the rising and setting of the stars and the movements of the earth, who set up the stars as stations for the ascent and descent of the souls . . .

We beg you to take an oath that these revered doctrines will not be revealed to profane ears but that the entire teaching of divinity will be made known only to those equipped with pure splendor of mind, whom an uncorrupted soul has led to the right path of life, whose loyalty is above reproach, whose hands are free of all crime. Receive, therefore, the detailed account which with the greatest trepidation of spirit we have promised you.

—Firmicus Maternus, Matheseos Libri VIII, 4th century CE