Knights fighting Snails

“As anyone who is familiar with 13th and 14th century illuminated manuscripts can attest, images of armed knights fighting snails are common.”

Often, the snails fare pretty well in the fight.

What is the significance of the snail imagery? Nobody really knows for sure, and it’s not obvious from context. One possibility is that the snail stands in for some contemporary figure or group, like in an editorial cartoon. Another is that it’s a sort of meme, a joke that the young men drawing marginalia learned and copied from the works of their peers.