“The Brahmâtma, the chief of the Hindu initiates, had on his headgear two keys, symbol of the revealed mystery of life and death, placed cross-like; and, in some Buddhist pagodas of Tartary and Mongolia, the entrance of a chamber within the temple, generally containing the staircase which leads to the inner daghôba, and the porticos of some Prachida are ornamented with a cross formed of two fishes, and as found on some of the zodiacs of the Buddhists. We should not wonder at all at learning that the sacred device in the tombs in the Catacombs, at Rome, the ”Vesica piscis”, was derived from the said Buddhist zodiacal sign. How general must have been that geometrical figure in the world-symbols, may be inferred from the fact that there is a Masonic tradition that Solomon’s temple was built on three foundations, forming the “triple Tau”, or three crosses.
In its mystical sense, the Egyptian cross owes its origin, as an emblem, to the realization by the earliest philosophy of an androgynous dualism of every manifestation in nature, which proceeds from the abstract ideal of a likewise androgynous deity, while the Christian emblem is simply due to chance. Had the Mosaic law prevailed, Jesus should have been lapidated. The crucifix was an instrument of torture, and utterly common among Romans as it was unknown among Semitic nations. It was called the “Tree of Infamy”. It is but later that it was adopted as a Christian symbol; but, during the first two decades, the apostles looked upon it with horror. It is certainly not the Christian Cross that John had in mind when speaking of the “signet of the living God”, but the mystic Tau – the Tetragrammaton, or mighty name, which, on the most ancient kabalistic talismans, was represented by the four Hebrew letters composing the Holy Word.
The famous Lady Ellenborough, known among the Arabs of Damascus, and in the desert, after her last marriage, as Hanoum Medjouyé had a talisman in her possession, presented to her by a Druze from Mount Lebanon. It was recognized by a certain sign on its left corner, to belong to that class of gems which is known in Palestine as a “Messianic” amulet, of the second or third century, B.C. It is a green stone of a pentagonal form; at the bottom is engraved a fish; higher, Solomon’s seal; and still higher, the four Chaldaic letters – Jod, He, Vau, He, IAHO, which form the name of the Deity. These are arranged in quite an unusual way, running from below upward, in reversed order, and forming the Egyptian Tau. Around these there is a legend which, as the gem is not our property, we are not at liberty to give. The Tau, in its mystical sense, as well as the crux ansata, is the Tree of Life.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 