



It also first described the Horus Heresy, the civil war of the 30th millennium in which nine of the Legions converted to the worship of the Chaos Gods and rebelled against the Emperor. It introduced the original 20 Space Marine Legions as well as their Primarchs. The book Realm of Chaos: The Lost and the Damned (Rick Priestley and Bryan Ansell, 1990) was the first book from Games Workshop to give a backstory for the Space Marines. Space Marines were first introduced in Warhammer 40,000: Rogue Trader (1987) by Rick Priestley, which was the first edition of the tabletop game. See also: List of Warhammer 40,000 novels
