The Arachosian Empire, also known as the Empire of the Arachosians or as the Great Empire of the Mighty Arachosians, was a galactic empire in existence from 280-354 AH. The Arachosian Empire was established by the Arachosians, a aggressive and war-like species hailing from the Crones Galaxy, who had entered the Caladarian Galaxy in 249, after nearly eight centuries of migration across the Extra-Galactic Void. The Arachosians had quickly infiltrated into the Galactic Borderlands, conquering most of that region within three decades, before pushing into the Wild Marshes, alongside the southern and eastern spans of the Outer Borderlands. By the 320s, the Arachosians also dominated parts of the Middle Territories as well. Under the leadership of their greatest emperor, Sargon the Conqueror (r. 322-36), the Arachosians waged war against the ancient Millian Empire, eventually conquering it by 330. They then advanced as far as the outskirts of the Central Core, subduing numerous states and kingdoms. Sargon's death in 336, however, prevented the consolidation of his conquests. The Empire effectively ceased to exist as a array of noblemen, regional satraps, military officers, court officials, and others squabbled with each other. Eventually, by 353 only six of them were left: Naradius and his son Isidius; Tudiya; Sennacherib; Shishak; and Xerxes. These proclaimed themselves sovereigns and divided the empire amongst themselves. With this, the Arachosian Empire officially ceased to exist.