The Hurrians are attested from the late third millennium BCE in northern Mesopotamia, Syria and eastern Anatolia, and their language belongs to no large family. Its only established relative is Urartian, the language of the later kingdom around Lake Van. It was written in cuneiform, and the longest single Hurrian document is a letter from a king of Mitanni to an Egyptian pharaoh, found in the Amarna archive.
Mitanni, the state the Hurrians dominated in the second millennium, was a major power alongside Egypt, Hatti and Assyria, exchanging princesses and treaties with all three, and its capital has never been located. Its ruling class carries a puzzle that has never been resolved. A number of royal names, a treaty invoking deities whose names resemble Mitra, Varuna, Indra and the Nasatyas, and a horse training manual using Indo-Aryan numerals together point to an Indo-Aryan element inside a Hurrian speaking state, and how that element arrived is still argued.
Hurrian political independence ended with the Assyrian and Hittite partition of Mitanni in the fourteenth century BCE, but the population and its gods did not disappear with it. They were absorbed into both empires, which is why so much of what survives of Hurrian religion is preserved in a language other than Hurrian.