George was a pirate, but he wasn’t a very good pirate.
After a long day of piracy, he’d change into his pajamas, make a cup of herbal tea, and read for a while.
Sometimes, the other pirates would steal his clothes while he slept, and George would have to go out in his pajamas.
Usually, he’d go shopping for new clothes, but sometimes he was woken up by a fight.
He fought well in them.
So well, other pirates began to wear pajamas while going into battle.
Not having pockets make it hard to carry ammunition for their flintlocks, though.