The Old Imperium was a term used to describe the Empire that was ruled by the Corrinos and later the Atreides. The Old Imperium initially spanned the known universe following the Butlerian Jihad, which banned the use of thinking machines. After the death of the God-Emperor Leto II, humankind exploded across unknown space, away from the boundaries of the Empire during a time that is known as The Scattering. Thereafter, the term 'Old Imperium' fell into use to describe the difference between what was the Corrino/Atreides Empire and the rest of the known universe.