THE earliest inhabitants of Britain are supposed to have been a branch of that great family known in history by the designation of Celts.Thomas Bulfinch
Random Internet browsing turned this up & I must say I howled with laughter given how much some people insist pants are men's clothing & men's clothing only.
When the Romans first invaded Britain they had their first encounter with braccae ~ the word from which we derive the term breeches ~ an item of clothing primarily worn by Celtic men, though not unknown to women. They were typically trousers that reached to the knee, or in the colder north, to the ankle with a drawstring at the waist. The Romans were not impressed & thought the Celtic men terribly effeminate because, as we all know, real men wear togas!