Based on the legends, Movses Khorenatsi attributed the founding of Garni to Hayk, the great-grandson of the ancestor Hayk, whose grandson, after Garnik, was allegedly named Garni. It is believed that the temple was dedicated to the God of Sun – Areg-Mihr.

The Armenian kings, particularly Trdat, considered Mithras their god-patron. It seemed natural that Trdat, after his victory over the mighty Rome and his coronation, would return to his homeland and build the temple of Garni on his throne, dedicated to his patron god – Mihr. Mihr, as a symbol of light, truth, was often depicted fighting a bull (symbolizing darkness).