A galero (pl. galeri; L. galerum, pl. galera) in the Roman Catholic Church is a large, broad-brimmed tasseled hat worn by clergy. Over the centuries the galero was eventually limited in use to individual cardinals as a crown symbolizing the title of Prince of the Church. The red galero was first granted to cardinals by Pope Innocent IV in 1245 at the First Council of Lyon. Tradition in the Archdiocese of Lyon is that the red color was inspired by the red hats of the canons of Lyon. According to Noonan, Pope Innocent wanted his favorites to be distinct and recognizable in the lengthy processions at the council.
The cardinal Jean Cholet used his galero to crown Charles of Valois in 1285 at Girona during the Aragonese Crusade, pronouncing him King of Aragon, and resulting in roi du chapeau ("king of the hat") becoming Charles's nickname.
When creating a cardinal, the Pope used to place a scarlet galero on the new cardinal's head in consistory, the practice giving rise to the phrase "receiving the red hat." In 1969, a papal decree following the Second Vatican Council ended the use of the galero as an act of humbling the Church hierarchy. It was deemed that by removing such elaborate regalia, the people could better identify with their pastoral leaders. Today, only the scarlet zucchetto and biretta are placed over the heads of cardinals in consistory. A few cardinals from eastern rites wear distinctive oriental headgear. However, some cardinals continue to obtain galeri privately so that the old ceremony of its suspension over their tombs may be observed.
When a cardinal dies, it is traditional that his galero be suspended over his tomb, where it remains until it is reduced to dust, symbolizing how all earthly glory is passing. It is said that when it falls, the cardinal's soul has entered Heaven. In the United States, where only a few cathedrals have crypts, the galeri of past archbishops who were cardinals are suspended from the ceiling. Some of the Cathedral churches in the United States that hang the galeri of past Cardinals from their ceilings are:
The galero (or "ecclesiastical hat") is still in use today in ecclesiastical heraldry as part of the achievement of the coat of arms of an armigerous Roman Catholic cleric. The galero replaces the helmet and crest, because those were considered too warlike for the clerical state. The color of the galero and number of tassels indicate the cleric's place in the hierarchy. Depiction in arms can vary greatly depending on the artist's style, but even when it looks like a cappello romano with tassels, in heraldry it is still considered a galero.