There was a god named Perseous that had a journey of getting Medusa’s head.
While going home, Perseous found a princess, Andromeda, that was tied in a rock in the sea(Perseous can fly) and saved her and wanted to marry her.
But Andromeda’s uncle also wanted to marry her, so he attacked Perseous.
Perseous said “The ones who trust me close your eyes!”
And revealed Medusa’s head.
But,Andromeda’s parents(including Cassiopeia)turned into stones.
Seeing how sad perseous and Andromeda was,Perseous father Zeus made Cassiopeia and cepheus into constellations,and that was the tale that Cassiopeia turned into a constellation.
The funny thing in this book that I think is that how could Andromeda’s uncle wanted to marry her?!π