Bishops alone, including of course the pope and his cardinals, are entitled to wear the pretiosa and auriphrygiata; the others wear the mitra simplex.
He is invoked with his double Mitra in some dozen hymns.
At mass and vespers the mitra simplex may be substituted for it in the same way as the auriphrygiata for the pretiosa.
Powerful as Indra is in the celestial world, Mitra and Varuna preside over night and day.
According to the Roman Caeremoniale the bishop wears the mitra pretiosa on high festivals, and always during the singing of the Te Deum and the Gloria at mass.
According to the 14th Roman ordo, of 1241, the pope places on the emperor's head first the mitra clericalis, then the imperial diadem.
He proves conclusively that the mitra mentioned by Theodulph of Orleans (Paraenes.
With Mitra and Varuna (Grassmann, Warterbuch, s.v.); in Zend, according to Bartholomae (Altiranisches Warterbuch, s.v.), from the earliest literature, the Gathas, there is nothing definite to be learnt regarding Airyaman.
Other powers of light, such as Mitra the god of day (Iranian Mithra), survived unforgotten in popular belief till the later system incorporated them in the angelic body.