Horus as bright as the sun was explained by a tale, known as "The Contendings of Horus and Seth". In this tale, it was said that Set, the patron of Upper Egypt, and Horus, the patron of Lower Egypt, had battled for Egypt brutally, with neither side victorious, until eventually the gods sided with Horus. As Horus was the ultimate victor he became known as "ḥr.w wr" "Horus the Great", but more usually translated "Horus the Elder". In the struggle, Set had lost a testicle, and Horus's eye was gouged out. Horus represented the eclipsing binary Algol in the Calendar of
The Horus Heresy (novels) Legion the "Sons of Horus" in his honour, while also leaving him in charge of the rest of the Crusade; the Emperor meanwhile returns to Terra, where in relative isolation he undertakes a secret project to which not even Horus is privy. The focus and perspective of the novel centres on a Space Marine Captain, Garviel Loken, leader of the Luna Wolves' 10th Company. He becomes a member of the Mournival, an informal advisory body to Horus, and participates in Crusade campaigns against anti-Imperial human populations and aliens, referred to in the series as "xenos". The story also hints at