Symbol: A phoenix.
Mitra worship is the state religion of Aquilonia.
Strongly present in Argos, The Border Kingdom, Brythunia, Corinthia, Khauran, Nemedia, Ophir, and Zingara.
Mitra's name and beliefs are known across the world.
Mitra worship is exclusive - worshippers are required to honour no other gods.
The dominant religion in a large proportion of the world's kingdoms.
The Church of Mitra is pretty much the only benevolent society in Hyboria. If you can pay, they can provide many services. If you have no gold, they will make a genuine and honest attempt to get some service from you in return. For example, if you are homeless, go to a temple. They will feed you and give you a bed for the night. You will have to perform some work (they are not a charity) but the work will not be oppressive.
Mitra is the one and only god. Worship of other gods is heresy.
Converting others is the highest service one can make to the church.
Followers and artifacts of Set are vile and must be destroyed.
Every person must lead a virtuous life.
Tradition is good. Innovation is bad.
Tolerance of gender, race, preference.
Honesty.
Honour.
Trust.
Proper treatment for those in your care. Parents have a duty to provide for their children, kings and queens must care for their subjects, slave owners must care for their slaves.
Earning your way.
Wholesome fun (sports, music, dancing and so on).
Tolerance of other religions.
Mistreating those in your care.
Betraying someone.
Breaking an oath.
Lying.
Giving or accepting charity.
Nameless Cults ch.3, p.35.