In the 1840s and 1850s, a curious tradition emerged - Vinegar Valentines. (They were also known as Penny Dreadfuls).
One might send a vinegar valentine (featuring a caricature and a nasty or mean poem) to someone you didn't like. At one point they accounted for more than fifty percent of all Valentine's mail!
Cruel and a bit twisted, these dark Valentines are intriguing to look at through the lens of history.