Flipping through an illustrated manuscript from the 13th century, you’d be forgiven for thinking that Jesus loved a good fart joke. That’s because the margins of these handmade devotional books were filled with imagery depicting everything from scatological humor to mythical beasts to sexually explicit satire. Though we may still get a kick out of poop jokes, we aren’t used to seeing them visualized in such lurid detail, and certainly not in holy books. But in medieval Europe, before books were mass-produced and reading became a pastime for plebes, these lavish manuscripts were all the rage—if you could afford them. The educated elite hired artisans to craft these exquisitely detailed religious texts surrounded by all manner of illustrated commentary, known today as marginalia.