At Xerxes' accession, trouble was brewing in some of his domains. A revolt occurred in Egypt, which seems to have been dangerous enough for Xerxes to personally lead the army to restore order (which also gave him the opportunity to begin his reign with a military campaign). Xerxes suppressed the revolt in January 484 BC, and appointed his full-brother Achaemenes as satrap of the country, replacing the previous satrap Pherendates, who was reportedly killed during the revolt. The suppression of the Egyptian revolt expended the army, which had been mobilized by Darius over the previous three years. Xerxes thus had to raise another army for his expedition into Greece, which took four years. There was also unrest in Babylon, which revolted at least twice against Xerxes. The first revolt broke out in June or July of 484 BC and was led by a rebel of the name Bel-shimanni. Bel-shimmani's revolt was short-lived, Babylonian documents written during his reign only account for a period of two weeks.