The biretta (Latin: biretum, birretum) is a square cap with three or four peaks or horns, sometimes surmounted by a tuft. Traditionally the three peaked biretta is worn by Roman Catholic clergy and some Anglican and Lutheran clergy. The four peaked biretta is worn as academic dress by those holding a doctoral degree from a pontifical faculty or pontifical university. Occasionally the biretta is worn by advocates in law courts, for instance the advocates in the Channel Islands.
The origins of the biretta are uncertain. It is mentioned as early as the tenth century. One possible origin is the academic cap of the high Middle Ages, which was soft and square. This is also the ancestor of the modern mortarboard used today in secular universities. The biretta seems to have become a more widely used as an ecclesiastical vestment after the synod of Bergamo, 1311, ordered the clergy to wear the "bireta on their heads after the manner of laymen." The tuft or pom sometimes seen on the biretta was added later; the earliest forms of the biretta did not bear the device.
The biretta is used by all ranks of the Latin clergy from cardinals to priests, deacons and seminarians. Those worn by cardinals are scarlet red and made of silk. After the Second Vatican Council the ceremony of giving the galero to cardinals was replaced with giving the biretta. The biretta of a bishop is amaranth in color, while those worn by priests, deacons, and seminarians are black. The pope does not make use of the biretta, instead wearing the more ancient camauro, which Pope Benedict XVI has brought back into use.