 Originating from Terra (Earth), it is an interstellar crusade that claims the galaxy as the rightful domain of Humankind, and aims to reunite the multitude of scattered human colonies remaining from earlier space exploration under the domain of an "Imperium of Man".Organised in numerous expeditions, the Crusade fields huge fleets and vast armies; at its forefront, led by the Primarchs, are Legions of Space Marines genetically-enhanced supersoldiers numbering in the millions.Over the course of two Terran centuries, the Crusade has reached star systems more than 50,000 light years away from its original staging point in the Sol (Solar) System, has assimilated millions of worlds into the Imperium, and has given Humankind a dominant position among the galaxy's species.