Cirta, while the south, which included the Aurès Mountains and was threatened by raids, became Numidia Militiana, "Military Numidia", with capital at the legionary base of Lambaesis. Subsequently Emperor Constantine the Great reunited the two provinces in a single one, administered from Cirta, which was now renamed Constantina (modern Constantine) in his honour. Its governor was raised to the rank of consularis in 320, and the province remained one of the six provinces of the Diocese of Africa until the invasion of the Vandals in 428, which began its slow decay, accompanied by desertification. It was restored to Roman rule after the Vandalic War, when it became part of the new Praetorian prefecture of Africa. Architecture The term “Royal Numidian Architecture” was coined for the monuments that were constructed by the Numidian kings. These monuments consist of tombs, tumuli and sanctuaries. Some examples of these structures are the mausoleum of Thugga, the tomb of Beni Rhenane, a tomb at Henchur Burgu in Djerba as well as two tumulus tombs known as the Madghacen and the Royal Mausoleum of Mauretania. There are also altars that were built at Simitthus and Kbor Klib. All of these monuments were built within the area ruled by Massinissa and his descendants. Major cities Numidia became highly romanized and was studded with numerous towns. The chief towns of Roman Numidia were: in the north, Cirta or modern Constantine, the capital, with its port Russicada (Modern Skikda); and Hippo Regius (near Bône), well known as the see of St. Augustine. To the south in the interior military roads led to Theveste (Tebessa) and Lambaesis (Lambessa) with extensive Roman remains, connected by military roads with Cirta and Hippo, respectively. Lambaesis was the seat of the Legio III Augusta, and the most important strategic centre. It commanded the passes of the Aurès Mountains (Mons Aurasius), a mountain block that separated Numidia from the Gaetuli Berber tribes of the desert, and which was gradually occupied in its whole extent by the Romans under the Empire. Including these towns, there were altogether twenty that are known to have received at one time or another the title and status of Roman colonies; and in the 5th century, the Notitia Dignitatum enumerates no fewer than 123 sees whose bishops assembled at Carthage in 479. Episcopal sees See Numidia (Roman province)#Episcopal sees. See also List of Kings of Numidia Numidians Numidian cavalry Roman Libya