There was a mystery religion of the 1st-4th century of the Roman Empire that was inspired by the worship of the proto-Indo-Iranian god, Mitra. It was particularly popular with the Roman military and involved complex and graded initiation ceremonies, replete with ritual meals and unique handshakes.
As a member of the ahuric triad, (which also include Ahura Mazda and Ahura Berezaiti) Mithra Avestan [Mica, to his friends] was the divinity (yazata) of contracts and oath — a judicial figure, an all-seeing protector of Truth, as well as the guardian of cattle, the harvest and of The Waters.
One of three judges at the Chinvat — the “bridge of separation” that all souls must cross — Mithra was an exalted figure. He was undeceivable, infallible, eternally watchful, and never-resting.
Mithra is described in the Avesta scriptures and prayers as:
Litany to the Sun
Homage to Mithra of wide cattle pastures
Whose word is true, who is of the assembly
Who has a thousand ears, the well-shaped one
Who has ten thousand eyes, the exalted one
Who has wide knowledge, the helpful one
Who sleeps not, the ever wakeful.
We sacrifice to Mithra, The lord of all countries, Whom Ahura Mazda created the most glorious, Of the supernatural yazads. So may there come to us for aid, Both Mithra and Ahura, the two exalted ones. I shall sacrifice to his mace, well aimed against the skulls of the Daevas.
We can appreciate were some of today’s religions [no names] and secret societies [nope — no names] got their ritualistic observances and practices.
[Ed: The ethnic Kurdish group, so persecuted in Iraq today, deny any connection of their faith to Zoroastrianism. Nevertheless, the word Yazidi is almost certainly, one would think, related to the word yazata (see above).]
PS. Together with the Vedic common noun mitra, the Avestan common noun miθra derives from proto-Indo-Iranian *mitra, from the root mi- “to bind”, with the “tool suffix” -tra- “causing to.” Thus, etymologically mitra/miθra means “that which causes binding”, preserved in the Avestan word for “covenant, contract, oath”. Perhaps here is also the origin of the Roman fasces, from whence comes the word “fascism”..