Mitra is a divine concept that is part of a number of separate religious traditions.
Variations of the Word "Mitra"
Mitra is also sometimes spelt (and pronounced): Mitras, Mithras, Mithra, Mihr, Mehr, and Meher.
Historical Mention of Mitra
In the Avesta, a text considered sacred in Zoroastrianism, Mitra is mentioned.
In the Rigveda, a text considered sacred in Hinduism, Mitra is mentioned.
A religion, sometimes given the name Mithraism, of which is throught to be what Catholicism developed from, also makes mention of Mitra.
My understanding is that Mitra is an Abstract Concept. And in particular a Virtue. And thus an Angel.
One that was taught through Allegory. And, as was often done with abstract concepts, was Anthropomorphised. And even associated with certain objects and symbols.
My understand is that Mitra is the Promise. Or, in other words, that if you tell someone else you are going to do something, then you should do your best to do it.
Some people also call this giving your word and swearing.
Things Named Mitra
The word "mitra" and its variations, are used to name or are part of the name of various things....
Mitra is used as an Iranian girls' name.
The seventh month of the Iranian calendar is named: Mehr.
There is a Zoroastrian and Iranian festival called Mehregan.
Historical Artifacts Related to Mitra
Vatican Connection to Mitra
I've read that the Vatican was built on the grounds of a temple dedicated to Mitra. That there are still many many Mitra related statues and other artifacts at the Vatican. And that many many of the Catholic rituals mimic rituals that were once done by those who worshiped Mitra.