The Catholic monks tonsure is an unusual thing, I always thought. It made me wonder what it was and why it was done. You never see it nowadays but, at one time, it was widespread.
The Catholic monks tonsure represents the crown of thorns of Jesus. It represented their vow of following Christs example. It seems that, over the years, two types of tonsures have developed. These are:
1. A circular shaved spot on the top of the head (see picture below).
2. A small ring of hair around the head (see picture below). Because of receding hairline, etc. this often became a ‘horshoe’ of hair around the back and sides of the head.
(this is a picture of Martin Luther)
In some orders, such as the Passionist Order I believe, they used to shave a cross on the top of the head when they first took their vows. After this, they’d resorted to one of the more common types described above.
During WWII they ceased tonsuring the monks. This was because the Germans often assumed someone who was ‘disguised’ as a monk was really a spy. And so, to prevent monks imprisonment and to preserve their lives, they allowed the monks to no longer tonsure their hair.
Since then the custom of tonsuring monks has not been reinstated as a requirement in any religious order (at least, as far as I know). Nowadays, with razors, they just simple shave off all their hair every two weeks or so (sort of like someone in the military).