It may of course be said that this was in external matters only, and that the “Persian furniture” which excited Horace’s wrath[783] might if it stood alone be looked upon as merely a passing fashion; but the Court ceremonial introduced by Diocletian argues a steady tendency towards Persian customs and forms of government that must have been in operation for centuries. The household of a Julian Caesar was no differently arranged from that of a Roman noble of the period, and his title of Prince of the Senate showed that he was only looked upon as the first of his equals. But Diocletian was in all respects but language a Persian emperor or Shah, and his style of “Lord and God,” his diadem, his silken state dress, the elaborate ritual of his court, and the long hierarchy of its officials, were all designed to compel his subjects to recognize the fact[784]. As usual, the official form of religion in the Roman Empire had for some time given indications of the coming change in the form of government. The sun had always been the principal natural object worshipped by the Persians, and a high-priest of the Sun-God had sat upon the Imperial throne of Rome in the form of the miserable Heliogabalus. Only 13 years before Diocletian, Aurelian, son of another Sun-God’s priestess and as virile and rugged as his predecessor was soft and effeminate, had also made the Sun-God the object of his special devotion and of an official worship. Hence Diocletian and his colleague Galerius were assured in advance of the approval of a large part of their subjects when they took the final plunge in 307 A.D., and proclaimed Mithras, “the Unconquered Sun-God,” the Protector of their Empire[785].