The Jewish headresses of the priests in the temple, as well as the crowns of the royalty in both Jewish and Pagan life influenced the mitre. Eastern Catholic and Orthodox bishops wear a mitre that looks like a traditional crown, and in the West it evolved from Jewish High priests mitres into the present form which reminds us of the tounges of fire that settled on the heads of our Lady and the Apostles on Pentecost.
With all it’s faults this wikipedia article is fairly good, and uses the Catholic Encyclopedia as a source. I post it primarily for the pictures.
Most Protestants get their information from two main sources, Alexander Hislop who was a very anti-catholic Anglican Bishop, his work has been debunked time and time again, but it is still one of the two Bibles of Anti-Catholics. He claims that the Mitre was derived from fish hats that priests in Babylon wore. There is no connection.
Pick up a copy of Karl Keating’s book, Catholicism and Fundamentalism: The Attack on “Romanism” by “Bible Christians” it will explain how deceptive the Hislop and other anticatholic books are, and why honest historians feel they are not worth the paper they are prinied on.