Changes

The '''Codex Astartes''' is a vast tome detailing the tactics, organization, markings and rituals of the [[Space Marines]]. Written after the [[Horus Heresy]] by the [[Primarch]] of the [[Ultramarines]] [[Roboute Guilliman]] the Codex is followed without question by the Ultramarines and their successors. Many other chapters also follow the Codex, though not always as strictly as the Ultramarines, and all chapters that do follow the Codex are known as Codex Chapters. The [[Ultramarines]] battle brothers often memorise passages of the codex so that the entire chapter has the wisdom of the codex within its companies.