Short answers, pulled from the story.
The oldest known trousers were found at the Yanghai cemetery in Turpan, Xinjiang, in present-day western China. Made of wool with straight legs and wide crotches, they date to between the thirteenth and the tenth century BC and were likely made for horseback riding.
The English word trousers comes from triubhas, the Gaelic name for a type of tartan trousers worn by Scottish Highlanders, anglicized as trews. Scots, which did not fully undergo the Great Vowel Shift, sometimes still pronounces trousers with a vowel close to the original Gaelic.
Republican Rome viewed the draped clothing of Greek and Minoan culture as a symbol of civilization and saw trousers as the mark of barbarians. As the empire expanded beyond the Mediterranean, the warmth trousers provided led Rome to adopt two types, the snug feminalia and the loose, ankle-closed braccae.
Representative Charlotte Reid became the first woman to wear trousers in the US Congress in 1969. Women were not allowed to wear trousers on the US Senate floor until 1993, when Senators Barbara Mikulski and Carol Moseley Braun wore them in defiance of the rule.
Denim Day is an annual protest held on the 22nd of April in which people wear jeans against sexual violence. It grew from a 1998 Italian Supreme Court of Cassation ruling that overturned a rape conviction because the victim wore tight jeans, prompting protests later organized into an annual event by Patricia Giggans of the Los Angeles Commission on Assaults Against Women.
Women's trousers often lack functional pockets and sometimes have Potemkin pockets, a fake slit sewn shut. In 2018, journalists at The Pudding found that the pockets in women's jeans were on average 48 percent shorter and 6.5 percent narrower than men's, with fewer than half able to fit a thin wallet.