"There are three distinct forms of the Cross. The first is called the Tau. It closely resembles the modern letter T, consisting of a horizontal bar resting on a vertical column, the two arms being of equal length. An oak tree cut off some feet above the ground and its upper part laid across the lower in this form was the symbol of the Druid god Hu. It is suspected that this symbol originated among the Egyptians from the spread of the horns of a bull or ram (Taurus or Aries) and the vertical line of its face. This is sometimes designated as the hammer Cross, because if held by its vertical base it is not unlike a mallet or gavel. In one of the Qabbalistic Masonic legends, CHiram Abiff is given a hammer in the form of a Tau by his ancestor, Tubal-Cain. The Tau cross is preserved to modern Masonry under the symbol of the T square. This appears to be the oldest form of the Cross extant. The Tau Cross was inscribed on the forehead of every person admitted into the Mysteries of Mithras. When a king was initiated into the Egyptian Mysteries, the Tau was placed against his lips. It was tattooed upon the bodies of the candidates in some of the American Indian Mysteries. To the Qabbalist, the Tau stood for heaven and the Pythagorean tetractys. The Caduceus of Hermes was an outgrowth of the Tau Cross." ― Manly P. Hall - The Secret Teachings of All Ages
