The Slovenes gave way before the pressure of the Germans who swept through the Alps and down the Danube and forced the Slovene vojvodes to acknowledge their suzerainty and accept their religion. The Germans would doubtless have succeeded in obliterating them had not the Magyar invasion weakened their offensive. The Slovenes, however, were left a wrecked nationality whose fate became blended with that of the Habsburg possessions and who against the forces of geography--which firmly bound them to the Croats--were politically riveted to the Habsburg north. This division was therefore the result of forces created by man and changeable by him. The Croats settled in the northwestern half of the territory south of the Slovenes; the Serbs roughly in the southeastern part of it. Here geographical influences--the direction of the rivers and the Dinaric ridges--combined with divergent political and economic possibilities, produced a dualism. The Croats on the Save and its tributaries naturally expanded westward and aspired to closer connection with the sea where their struggle with the remnants of Roman civilization and a superior culture absorbed their energies. They developed out of their tribal state more quickly, while the Serbs, further inland and amid more difficult surroundings, developed more slowly. The people who lived along the Save aspired to control the Dalmatian coast which military and geographical authorities claim can best be held from the mainland. The people who lived in Montenegro or along the Morava, which was the gateway to the peninsula, would naturally expand south and east toward the other cultural center, Constantinople, and thus seek to dominate the Balkan peninsula. In both cases, the attraction proved too much for feudal kings and led to the formation of cosmopolitan empires instead of strong national monarchies. The kingdoms of Croatia and Serbia thus parted company politically. The former became a separate kingdom attached to Hungary in 1102 and to the Habsburg dynasty in 1527, while the Serbs began their expansion under the Nemanja dynasty late in the twelfth century and almost realized the dominion over the Balkans under Stephen Du[s]an in the fourteenth century. This political, geographical, and economic dualism became still greater when in 1219 the Serbs cast their lot with orthodoxy. The Croats, like the Slovenes, adopted Roman Catholicism, the Latin alphabet, and the culture of Rome. The Serbs accepted Greek Orthodoxy, the Cyrillic alphabet, and the culture of Constantinople.