Why is (are?) Pilates called Pilates?

Search: pilates

Why: Is it a proper noun? Do I have to capitalize it?

Answer: It was developed by German gymnast, diver, bodybuilder, boxer, circus performer, and self-defense trainer Joseph Pilates. While interned on the Isle of Man during WWI, he developed the exercise system - which he called Contrology - as a combination of yoga and the movements of animals. Legend has it that his fellow inmates survived the great flu pandemic of 1918 due to the physical fitness he helped them achieve.

Source: Wikipedia

The More You Know: His father was a Greek gymnast and his mother was a German naturopath. The family's original Greek name was Pilatu, which would be a good name for exercises, too.