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) after (week of September 23), at number 33. Between the late–1980s introduction of the Horus Heresy and the start of this series publication in 2006, Games Workshop and affiliates released -branded products that expanded the concept's standing as "Warhammer 40,000" background material. The release of such works, which include literature independent of this series, continued ; the works may relate to it as prequels, sequels, or expansions of its stories. Pre-series Horus Heresy literature and other related works may have been superseded or rendered obsolete, while other similar material may no longer be authoritative even as it remains in Horus