The leotard made its debut back in 1828. A man who rode bareback on horses performed his act in his underwear because his costume hadn’t come back from the cleaners. Other performers realized the advantages of performing in a tight-fitting uniform, and adopted the costume. Then in 1859 a man named Jules Leotard amazed crowds with his trapeze performances while wearing a snug-fitting bodysuit. The name “leotard” became associated with him, and that’s what it was called from then on.
As the century progressed, competitive swimmers, runners, and circus performers began wearing even skimpier attire: legless drawers, similar to today’s male briefs—but usually with tights. Unfortunately for the athlete, these briefs were cut the same way in the front and the back, so they rose uncomfortably over the backside.
Source: “The Englishman’s Swimwear” by Richard Rutt. Costume, v 24: 69 – 84, 1990