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
Horus Heresy (fictional event) phases of the crusade, the Emperor promotes Horus Lupercal, his most trusted and versatile , to the position of Warmaster ( of Imperial armed forces), and overall leader of the Crusade. The Emperor then leaves the Crusade and returns to Terra, where he remains in relative isolation. He relegates administration of the Imperium to a civilian authority the and in an undertaking kept secret even from Horus, oversees efforts on his secretive . These actions, along with his father's refusal to reveal the nature of the Warp, test Horus' personal and mission-related resources, and exacerbate existing tensions among some of