There are two theories about the origin of Valentine’s Day. According to History.com, one is that the day derives from Lupercalia, a raucous Roman festival on February 15th where men stripped naked and spanked young maidens in the hopes of upping their fertility. (Okay … that is a little weird).
The second theory is that while the Roman Emperor Claudius II was trying to bolster his army, he forbade young men to marry, because apparently single men make better soldiers. In the spirit of love, St. Valentine defied the ban and performed secret marriages, History.com reports. For his disobedience, Valentine was executed on February 14th.