In passing, its interesting to know that the Emperor Hadrian established and supported another cult religion.
Here's Wikipedia description (an extract from the fuller entry on Hadrian):
Hadrian had Antinous deified as Osiris-Antinous by an Egyptian priest at the ancient Temple of Ramesses II, very near the place of his death. Hadrian dedicated a new temple-city complex there, built in a Graeco-Roman style, and named it Antinoöpolis.[227] It was a proper Greek polis; it was granted an Imperially subsidised alimentary scheme similar to Trajan's alimenta,[228] and its citizens were allowed intermarriage with members of the native population, without loss of citizen-status. Hadrian thus identified an existing native cult (to Osiris) with Roman rule.[229] The cult of Antinous was to become very popular in the Greek-speaking world, and also found support in the West. In Hadrian's villa, statues of the Tyrannicides, with a bearded Aristogeiton and a clean-shaven Harmodios, linked his favourite to the classical tradition of Greek love.[230] In the west, Antinous was identified with the Celtic sun-god Belenos.[231]
Hadrian was criticised for the open intensity of his grief at Antinous's death, ....] Nevertheless, his recreation of the deceased youth as a cult-figure found little opposition.[233] Though not a subject of the state-sponsored, official Roman imperial cult, Antinous offered a common focus for the emperor and his subjects, emphasising their sense of community.[234] Medals were struck with his effigy, and statues erected to him in all parts of the empire, in all kinds of garb, including Egyptian dress.[235] Temples were built for his worship in Bithynia and Mantineia in Arcadia. In Athens, festivals were celebrated in his honour and oracles delivered in his name. As an "international" cult figure, Antinous had an enduring fame, far outlasting Hadrian's reign.[236] Local coins with his effigy were still being struck during Caracalla's reign, and he was invoked in a poem to celebrate the accession of Diocletian.[237]
Why did Hadrian do that, because the handsome young man. Antinous, was his his devoted lover.