Perseus and Medusa
Beowulf is an epic Anglo-Saxon poem about a monster-slaying Viking hero named Beowulf. Sounds a bit like Perseus, right? In this story, Beowulf takes on two monsters: Grendel and then Grendel's mom. Grendel's mom turns out to be the harder monster to kill. This also links Beowulf and Perseus: both slay female monsters.
Psst. You can read a lot more about Beowulf on Shmoop. Just click here.