The ancestors of the modern Lithuanians were known as Balts and
probably reached the area from the south-east around 2000 BC. By
the 12th century the Balt peoples were split into tribal groups,
all practising nature religions.
The two main groups in Lithuania were the Samogitians in the west
and the Aukstaitiai in the east. In what is now south-west Lithuania
and in neighbouring parts of Poland were the Yotvingians, also a
Balt people, later to be assimilated by the Lithuanians and Poles.