The first people who came to live on the present territory of Lithuania in the Paleolithic Period (the second half of the 10-th millennium B.C.) were representatives of two cultures. Those who came from the banks of the middle Vistula river in the south-west settled here permanently. Those from the north-west of Europe used to reach these parts in small groups and leave again after some time. In late Paleolithic Period when the climate became colder, this migration stopped, the two peoples settled side by side and it was inevitable that they should mix.
In early Mesolithic Period, i.e. in the 8-th millennium B.C., the climate became warmer again, the deer retreated to the north and the people who had settled here in the Paleolithic Period, followed them. Those who stayed mixed with the fishermen who moved in from the west to form ethnic groups of Baltic culture. At the end of the 3-rd millennium B.C. the new wave of nomadic cattle raisers, who moved in from the south and south-west, brought corded pottery culture. The first typical Baltic culture of brushed pottery formed at the turn of the last millennium B.C. It was the time when the first hillforts and barrows appeared and the cremation of the dead was introduced. The first Baltic tribes emerged in the valleys of the Nemunas and Neris rivers in the period between the l-st and 4-th centuries A.D. to lay the foundations for the future Lithuanian nation, The Latvian, Yotvingian and Prussian tribes formed somewhat later. In the 9-th century the existence of the Baltic tribes was noted by travelers and historians.
J. Kudirka "THE LITHUANIANS"