Tetractys

The tetractys (τετρακτύς), or tetrad, or the tetractys of the decad is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular number. As a mystical symbol, it was very important to the secret worship of Pythagoreanism. There were four seasons, and the number was also associated with planetary motions and music. The first four numbers symbolize the musica universalis and the Cosmos as: Monad – Unity Dyad – Power – Limit/Unlimited (peras/apeiron) Triad – Harmony Tetrad – Kosmos The four rows add up to ten, which was unity of a higher order (The Dekad). The Tetractys symbolizes the four classical elements—air, fire, water, and earth. The Tetractys represented the organization of space: the first row represented zero dimensions (a point) the second row represented one dimension (a line of two points) the third row represented two dimensions (a plane defined by a triangle of three points) the fourth row represented three dimensions (a tetrahedron defined by four points) A prayer of the Pythagoreans shows the importance of the Tetractys (sometimes called the "Mystic Tetrad"), as the prayer was addressed to it. Bless us, divine number, thou who generated gods and men! O holy, holy Tetractys, thou that containest the root and source of the eternally flowing creation! For the divine number begins with the profound, pure unity until it comes to the holy four; then it begets the mother of all, the all-comprising, all-bounding, the first-born, the never-swerving, the never-tiring holy ten, the keyholder of all. As a portion of the secret religion, initiates were required to swear a secret oath by the Tetractys. They then served as novices, which required them to observe silence for a period of five years. The Pythagorean oath also mentioned the Tetractys: By that pure, holy, four lettered name on high, nature's eternal fountain and supply, the parent of all souls that living be, by him, with faith find oath, I swear to thee.