Tiara (Gr.), a species of high hat anciently worn by many eastern nations. Those of kings and priests were encircled by a sort of crown, whence the term tiara has been applied to the triple crown worn by the popes, which in turn bears a striking resemblance to the Persian royal tiaras and to those of the Assyrian kings, represented on the slabs at Nineveh. It is uncertain when the popes assumed the tiara. It was called regnwrn, or emblem of royalty, to distinguish it from the mitre. Pope Innocent III., in his sermon on St. Sylvester, says that the bishop of Rome uses the mitre everywhere and at all times, because his episcopal jurisdiction is universal, whereas he only uses the regnum or tiara occasionally and in his own dominions. The papal tiara was at first a conical cap, topped with a small round ball, and wreathed about the. forehead with a crown of gold. It retained this shape till Boniface VIII. (1294-1303) added to it a second crown, and Urban V. (1362-70) added a third. It kept to its first sharply pointed form till the beginning of the 16th century, when it assumed an oval shape, swelling out somewhat broad at top.

Fig. 1. - Persian Tiara.

Fig. 2. - Assyrian Tiara.

Fig. 8. - Tiara of the Pope.