Diocletian's Tetrarchy reforms of 296 altered Cyrenaica's administrative structure. It was split into two provinces: Libya Superior or Libya Pentapolis, comprising the above-mentioned Pentapolis, with Cyrene as capital, and Libya Inferior or Libya sicca, the Marmarica, which had by then gained a significant city, the port Paraetonium. Each came under a governor holding the modest rank of "praeses". Both belonged to the Diocese of the Orient, with its capital at Antioch in Syria, and from 370, to the Diocese of Egypt, within the praetorian prefecture of Oriens. Its western neighbor Tripolitania, the largest split-off from Africa proconsularis, became part of the Diocese of Africa, subordinate to the prefecture of "Italia et Africa". Following the Crete earthquake of 365, the capital was moved to Ptolemais. After the Empire's division, Cyrenaica became part of the East Roman Empire (Byzantine Empire), bordering Tripolitania. It was briefly part of the Vandal Kingdom to the west, until its reconquest by Belisarius in 533.