When considering the way the Indo-Europeans took to the west, it is important to realize that mountains, forests and marshlands were prohibitive impediments. Moreover, people need fresh water, all the more so when traveling with horses. The natural way from the Russian steppe to the west is therefore along the northern bank of the river Danube. This leads to the hypothesis that the western Indo-Europeans represent successive waves of migration along the Danube and its tributaries. The Celts evidently followed the Danube all the way to southern Germany. The ancestors of the Italic tribes, including the Veneti, may have followed the river Sava towards northern Italy. The ancestors of Germanic speakers apparently moved into Moravia and Bohemia and followed the Elbe into Saxony. A part of the Veneti may have followed them into Moravia and moved along the Oder through the Moravian Gate into Silesia. The hypothetical speakers of Temematic probably moved through Slovakia along the river Drava into western Galicia. The ancestors of speakers of Balkan languages crossed the lower Danube and moved to the south. This scenario is in agreement with the generally accepted view of the earliest relations between these branches of Indo-European. The western Indo-European vocabulary in Baltic and Slavic is the result of an Indo-European substratum which contained an older non-Indo-European layer and was part of the Corded Ware horizon. The numbers show that a considerable part of the vocabulary was borrowed after the split between Baltic and Slavic, which came about when their speakers moved westwards north and south of the Pripet marshes. These events are older than the westward movement of the Slays which brought them into contact with Temematic speakers. One may conjecture that the Venedi occupied the Oder basin and then expanded eastwards over the larger part of present-day Poland before the western Batts came down the river Niemen and moved onwards to the lower Vistula. We may then identify the Venedic expansion with the spread of the Corded Ware horizon and the westward migration of the Batts and the Slays with their integration into the larger cultural complex. The theory that the Venedi separated from the Veneti in the upper Sava region and moved through Moravia and Silesia to the Baltic Sea explains the "im Namenmaterial auffallige Ubereinstimmung zwischen dem Baltikum and den Gebieten um den Nordteil der Adria" (Udolph 1981: 61). The Balts probably moved in two stages because the differences between West and East Baltic are considerable.
