What is cardinal catholic hat?

The cardinal Catholic hat, also known as a cardinal's biretta or galero, is a distinctive ecclesiastical hat worn by members of the Catholic Church who have been ordained as cardinals. It is a four-cornered hat with three ridges or peaks. The hat is traditionally red, which symbolizes the cardinal's willingness to shed their own blood for the sake of the Gospel.

The use of the cardinal hat dates to the Middle Ages, when male church leaders wore various types of hats to signify their rank and authority. The galero was officially adopted as the cardinal's hat by the Roman Catholic Church in 1570 as part of the reform of the church's structure and administration.

Today, the cardinal hat is primarily worn during formal liturgical events and ceremonies, such as the installation of a new pope or the canonization of a saint. When a cardinal dies, their hat is traditionally hung in their cathedral as a symbol of their service to the church.