The two lines above Celestia should mean “In the year 100 of the reign of Celestia and Luna living eternally, the two sisters fought the god of chaos and inprisoned him forever.” the other hieroglyphs are the characters names.
this drawing is based on Seth fighting Apophis on the solar bark. Celestia is Ra/Osiris, Luna is Seth(I forgot to make her ears longuer)/Khons, Discord is Apophis and Harmony is Maat.