 A significant development was the 2012 initial release of the "Horus Heresy" miniatures wargame expansion, which repositioned the concept as a foreground element within the "Warhammer 40,000" gaming system while highlighting the importance of the Horus Heresy to Games Workshop's product lineup and the related universe.The expansion is reputedly developed in coordination with the book series, and includes new material and information about the Horus Heresy and the fictional universe; it joins the series and other works as an authoritative source of Heresy material and "Warhammer 40,000" background.The Black Library and Games Workshop have released novels, game rulebooks, and other products not branded or classified as "Horus Heresy", yet directly relating to story arcs or events described in the series.