It looks like the chastity belt was a Florentine invention of the '300; through its use, husbands leaving for war they ensured the fidelity of their wives who remained at home.

The thought that the ladies might not have limited themselves to spend the days between housework and prayers so tormented the Florentine nobles leaving for the war, that someone invented for them a kind of iron pant closed by a padlock, the key of which, of course, was held by her husbands.