The Roman Empire that Justinian inherited no longer stretched over the whole Mediterranean region. It has been reduced to its eastern Greek-speaking half. In the Balkans, it controlled the area occupied now by Greece, Macedonia, Bulgaria, Albania and Serbia, wich together made up the prefecture of Illyricum. Its northern frontier was the Danube River, north of which were various Germanic, Hun and Slavic peoples who made constant incursions into imperial territory but thus far had made no permanent settlements. In Asia, the prefecture of the Orient comprised an area west of a frontier that ran roughly from the eastern tip of the Black Sea south to the Euphrates River, and from there across the desert of Jordan to the Gulf of Aqaba. In Africa, it controlled Egypt, and the southern part of present-day Libya. The former Roman Western Empire was occupied by barbarian kingdoms: the Vandal kingdom in North Africa, the Visigoth kingdom in Spain, the Frankish kingdom in France and the Ostrogoth kingdom in Italy.