History, Early Period

Much of the region south of the Danube River was known as Noricum. The western uplands region between the upper Rhine River, the lower course of the Inn River, and the Bavarian and subalpine plateau was known as Rhaetia, an area which also included parts of modern-day Germany and Switzerland. The plains region in the east and southeast was known as Pannonia and included areas in present-day Hungary and Slovenia. The Romans invaded all three regions about 15 bc and made them provinces of the empire. Under Roman control, the provinces eventually became outposts for offensive and defensive action against various barbarian tribes. To a large extent Roman strategy was based on the fact that the region contains important passes through the Eastern Alps and thus commands vital transportation arteries between northern, southern, western, and eastern Europe. One of the first Roman military posts in the region was Vindobona (now Vienna), which was located on the site of a Celtic settlement on the edge of the Eastern Alps and on an arm of the Danube. Vindobona became an important strategic crossroad for two main trade routes and for numerous roads leading into the fertile basin of Niederosterreich. Carnuntum (now Petronell), east of present-day Vienna, was another important Roman center in the area.

As a result of periodic overpopulation and land hunger, combined with pressure from remote peoples and the attraction of the wealth of the peaceful Roman provinces, tribes of the Germanic peoples attacked the provincial frontiers at various times starting in ad 166. The frontiers completely broke down during the 4th century ad. Goths, Rugians, Lombards, Vandals, Ostrogoths, and Huns at one time or another crossed the Vienna Basin. The Alamanni advanced into Rhaetia, the Herulians captured Juvavum (now Salzburg), and the Goths advanced along the Drava (Drau) River.

The Slavs and the Avars moved into Pannonia from the east and southeast at about the same time the Germans invaded the northwest. By the mid-6th century the Bavarians had occupied Tirol, and the Alamanni had settled to the west. The Slavic peoples were split into northern and southern groups by Avars and Bavarians contending for control of the Danube River valley. The Avars left only superficial traces in the country, but the Slovenes built settlements in the depopulated valleys of the Eastern Alps. The Germans finally overwhelmed the Slovene settlements, which could not depend on a continuous stream of new settlers. In a few areas of what are now Karnten and Steiermark the Slovenes managed to establish permanent settlements.