The ancient Egyptians sometimes wore loincloths. The Romans also wore underwear. Both Roman men and women wore a loincloth or shorts called subligaculum. Women also wore a band of cloth or leather around their chest called a strophium.
During the Middle Ages men word linen shorts called braies but women did not wear knickers until the 19th century. Their only underwear was a long linen garment called a shift, which they wore under their dress. From the 16th century women wore corsets made with whalebone.
In the 19th century underwear became much more elaborate.
Where does the word does the word pants come from? It is derived from a character in Italian comedy called Pantalone. He wore garments that came down to his ankles (when most men wore ones that came to the knee). In 18th century England they were called pantaloons. In the 19th century the word became shortened to pants. In Britain pants came to mean long drawers that covered the whole leg. The garments worn over them came became known as trousers.
The word drawers was invented because underwear was drawn on. Where does the word knickers come from? It comes from a novel called History of New York by Diedrich Knickerbocker, supposedly a Dutchman living in New York (it was actually written by Washington Irving). In Britain the illustrations for the book showed a Dutchman wearing long, loose fitting garments on his lower body. When men wore loose trousers for sport they were sometimes called knickerbockers. However women's underwear were soon called knickerbockers too. In the late 19th century the word was shortened to knickers. In the USA women's underwear are called panties, which is obviously a diminutive of pants.
At the beginning of the 1800s women still wore a long nightie-like garment under their dress but it was now called a chemise not a shift. However after about 1800 they also wore drawers. Sometimes they came to below the knee or sometimes they were longer garments with frills at the bottom called pantalettes. However by the 1830s only girls not women wore pantalettes.
Today we still say a pair of knickers or panties. That is because in the early 19th century women's underwear consisted to two separate legs joined at the waist. They really were a 'pair'.
At first women's drawers were usually very plain but in the late 19th century they were decorated with lace and bands. In the Winter women often wore woolen knickers and woolen vests.
In the 19th century women's underwear were sometimes called bloomers. Elizabeth Miller invented loose trousers to be worn by women. The idea was promoted by Amelia Bloomer from 1849 and they became known as bloomers. In time long underwear became known as bloomers.
By the late 19th century in Britain men's underwear were called pants. Men also wore vests. Some men wore combinations, pants and vest in one garment.
In the 19th century women's underwear was usually open between the legs but in the 20th century closed knickers replaced them.
Meanwhile in 1913 Mary Phelps Jacob invented the modern bra. She used two handkerchiefs joined by ribbon.
In the 19th century knickers came down to the knee. In the 1920s they became shorter, down to the mid-calf. By the 1940s and 1950s many women wore briefs. Men's underwear also became shorter. The word drawers went out of use and they became known as underpants or pants. Y-fronts went on sale in the USA in 1935. They went on sale in Britain in 1938. Boxer shorts were introduced in the 1940s.