Word Geek

CONSTABLE
Now used as on official term for law enforcement officers, this word began in the horse stables. In ancient Rome, the official version was comes stabuli, literally meaning "count of the stable," or the head groom. By the 1200s, the Old French version, conestable, was used to refer to the head officer of a king's household and by the 1500s, the current use had arisen.

I'd never have guessed ... fascinating!