TIARA. — From the Greek τάρα σινοί-μοι of the φρίγον (turban) head covering, proper to the pope, of conical shape adorned with three crowns (= tri-regnum), surmounted (from the 16th century) by a small cross.
It is not used during liturgical functions, and the pope receives it from the hands of the cardinal protodeacon, as in ancient times, outside the Vatican Basilica, on the day of his solemn coronation after the solemn Mass, before the people. He then wore it during the solemn procession in which he went to take possession of the Lateran Archbasilica, from the time when he established his ordinary residence in the Vatican Palace. Today the pope wears it on his return from the celebration or attendance at the pontifical Mass.
It has a common origin with the mitre, resembling the Phrygian cap, used at the Persian court and later made the insignia of the Byzantine emperor. It seems to have been used by the popes at least from the 8th–9th century as a sign of their temporal power, perhaps from the time of Pope Constantine of Syria (708–15; cf. *Constitutum Constantini*, ed. K. Zeumer [1888], cap. 16). It had the form of a tall, pointed cone made of white cloth; around the lower edge ran a gold band (cf. the coins of Sergius III [904–11] and Benedict VII [974–83] representing St. Peter with a pointed conical cap). This head covering is to be distinguished from the *camelaucum*, which later became the liturgical mitre. Not before the 10th century did the gold band of the Phrygian cap become a crown, after 1256 crenellated, called the *regnum*. At the beginning of the 14th century, under Boniface VIII (1294–1303), the form was somewhat altered and a second crown was added (cf. the attempt of Hildebrand the archdeacon in 1059 to add the second crown); the third crown was added under Benedict XI (1303–1304) or Clement V (1305–14); hence the name *tri-regnum*. Innocent III indicates the mitre as 'for the priesthood'; the tiara 'for the kingdom'. The double crown has the same significance as the papal and imperial authority in analogy to the double crown of the emperor who wore above the clerical mitre the 'diadem of empire'. E. Eichmann explains the three crowns of the tiara in analogy to the three crowns of the emperor: the German at Aachen, the Lombard at Milan-Monza, and the Roman at Rome. The form of the papal coronation in the Roman Pontifical of 1506 instead declares the Pope to be 1) father of princes and kings, 2) rector of the world, 3) vicar of Christ. — See pl. V. BIBLICA.: J. Braun, *Die liturgische Gewandung im Occident und Orient*, Freiburg 1907, pp. 498–508; G. Ladner, *Die Statue Bonifaz VIII. in der Lateranbasilika und die Entstehung der dreifach gekrönten Tiara*, in *Römische Quartalschrift*, 42 (1934), p. 35 ff.; P. E. Schramm, *Zur Gestalt der päpstlichen Tiara*, in *Historische Zeitschrift*, 152 (1935), pp. 307–12; M. Righetti, *Manuale di liturgia*, I, Milano 1950, p. 536; F. Hermann, *Tre ritratti*