Great Crusade

The Great Crusade was the period in the early history of the Imperium of Man, lasting from approximately 798.M30 into the first decades of the 31st Millennium (approximately a little over two standard centuries), when the Imperium was expanding as it sought to bring all of human-settled space back under the control of a single ruler, the Emperor of Mankind. It would come to an end with the cataclysm of the Five Ruins.