Left to right: Jules Léotard, late 1860s; patent application for pantyhose, 1956; advertisement for pantyhose, 1960
French acrobat Jules Léotard (born 1838) developed the art of trapeze when he first performed a three bar aerial performance on November 12, 1859. For this feat he wore a one-piece jersey garment that in France was called a maillot. Worn by dancers, the body stocking was slangily referred to in English as 'tights', for obvious reasons. In 1867, Jules Léotard was immortalized by George Laybourne as the subject of his 1867 popular song "The Daring Young Man on the Flying Trapeze." Léotard died in 1870 from smallpox and the maillot soon became known as a leotard, officially entering the English vocabulary in 1886.
Seventy Years later, Ernest G. Rice filed for a U.S. patent for a garment that took the idea of the lower half of a leotard that combined sheer stockings with an opaque panty that eliminated the need for garter attachments and belts. Sixteen months later, on March 18, 1958, Rice was granted his patent and pantyhose hit the market the following year. Sales were slow at first, but when the miniskirt soared four inches above the knee in the late 1960s, pantyhose became a necessary addition in women's wardrobes, and would remain a staple until the late 1990s.
In the process of researching pantyhose history, I came across this interesting website.