Papyrus of Ani, British Museum (New Kingdom), a Book of the Dead.
Key myth
Every day Ra crosses the sky in his barque and every night passes through the underworld, fighting the serpent Apep. From the Fourth and Fifth Dynasties kings styled themselves his sons.
Where sources differ or caution applies. Ra is sometimes the creator himself, sometimes descended from Atum, sometimes fused with him. Texts do not agree and Egyptians did not require them to.