The Eastern Roman Emperor Justinian I, who had supported Hilderic, soon declared war on the Vandals, ostensibly to restore Hilderic. In June 533, Justinian sent an expeditionary force commanded by Belisarius which finally reached Africa in the beginning of September. Meanwhile, in Sardinia, which formed part of the Vandal domain, the governor Godas, a Goth, revolted against Gelimer and began to treat with Justinian as an independent sovereign. Gelimer, ignorant or contemptuous of Justinian's plans, sent a large army consisting of most of the available army in Africa under his brother Tzazo to crush the rebellion, meaning that the landing of Belisarius was entirely unopposed.