Darwin Day isn’t the only holiday this week, but here at Cambridge, we like to think that it’s the most important one: how can a day of roses and over-processed chocolates even compete with a tribute to groundbreaking intellectual achievement? Darwin revolutionized biology, theology, medicine, gender, politics, and literature, so I’ll bet has a thing or two to teach us about romance as well.

His 1871 study On the Descent of Man and Selection in Relation to Sex is just filled with Hallmark-worthy sweet nothings, so we’ve put his words into cards you can send your Valentine! You’re welcome.