The origins of Valentines day as a celebration are thought to have begun with the Roman festival of Lupercalia, where, to celebrate the mythological founders of Rome, the Romans would do very odd things.

The festival involved the sacrifice of a goat and a dog; the goat’s hide would be cut into strips and dipped in its blood, and priests, called Luperci, would then carry these strips and gently slap crop fields and women with them, with the latter being eager for this treatment as they believed that it would make them more fertile in the coming year.

Ancient.EU

That sounds more fun than trudging around looking for greetings cards.