Catholic monks used to be recognizable by their shaven crown, the so-called tonsure, sometimes also called the ‘corona’. This symbol of devotion was popular for a long time, but resistance arose in the course of the twentieth century. The Catholic Church abolished the tradition of the bald crown in 1972 by decree.
Lay brothers did not shave their crowns in the past. Its use was reserved for fathers. The first time the crown was cut was an important step in the training of the novices, the new monastics.
In some strict Catholic denominations, the tonsure is still practiced with the permission of the Pope. Incidentally, the use is not only known from Christianity. Also Egyptian priests used these practices to earlier times.