Notwithstanding this popularity, it is not easy to say exactly what god Mithras’ European worshippers considered him to be. If length of ancestry went for anything in such matters, he might indeed claim a greater antiquity than any deity of the later Roman Pantheon, with the single exception of the Alexandrian gods. Mithras was certainly worshipped in Vedic India, where his name of Mitra constantly occurs in the sacred texts as the “shining one,” meaning apparently the material sun[793]. He is there invoked in company with Varuna, generally considered the god of the sky, and therefore according to some, the prototype of the Greek Zeus and the Latin Jupiter[794]. His appearance in a similar connection in the sacred books of the Persians led the founders of the comparative study of religion to think that he must have been one of the primitive gods of their hypothetical Aryan race, and that his worship must go back to the imaginary time when Persians and Hindus dwelt side by side in the plains of Cashmere. But this theory is giving way before proof that the original home of the Indo-European race was Europe, and has been badly shaken by the discovery at Boghaz Keui of tablets showing that the gods Mithra and Varuna were gods of the Mitannians or Hittites[795] at some date earlier than 1500 B.C., and therefore long before the appearance of the Persians in history. If the worship of Mithras were not indigenous in Western Asia, it may therefore well have come there independently of the Persians[796].