Fencer of Minerva

ミネルバの剣士

Minerva no Kenshi

Princess Diana runs away from an arranged marraige and straight into the arms of slave traders who capture her and she is forced to become a slave. She finds her long lost childhood friend/love there, who happens to be the sworn enemy of her families throne, and becomes his, but of course with the family wanting her back all is not ideal. (Source: Anime News Network)