Although it is quite belated, I wondered what really the "Pegasus" is, when I wrote the previous note. 

I searched on the internet and found a website for the "Theoi Project" (https://www.theoi.com/Ther/HipposPegasos.html). Pegasus is a winged horse in Greek Mythology. 

According to Theoi, it was born from the blood flowing off the neck of beheaded Medusa (!) 

It is immortal and named after the spring of the Oceanus (one of the water deities, the eldest of the Titan family), as Pegasus was made to imitate the appearance of the spring. Because it was grown up for deities, it lived in the palace of Zeus. As a prancer, it was resistant about carrying mere mortals. 

But later, Bellerophon succeeded to ride and break Pegasus into battle against Chimera. After beating Chimera, Bellerophon was even more reckless and tried go beyond heaven, which invoked the wrath of Zeus. Then, Pegasus shook him off and went to back to Zeus. In modern times, Pegasus became regarded as the horse of Muses. 

These stories were unimagined. I'm curious how my publisher will go with the name of Pegasus.