Proto-Podlachians, tribe from borderlands.

Proto-Podlachians; suggested by the experts West-Slavonic tribe inhabiting the core of the Podlachia region (Podlasie). According to interdisciplinary research involving archeology, genetics and linguistics, this group is characterize as descendants of tribal Przeworsk-culture (strong on the Podlasie) and part of the Wielbark-population (those who have not migrated to the area of Chernyakhov culture)
Borderlands of Podlasie
That People was slavized in the time of migration of Slavs. The ethnic similarity to the groups living on the banks of Vistula River and their distinctiveness from the tribes living to the north  and east (Yotvingia and Krivichi land) of Podlachia , results that Proto-Podlachians are classified as part of Mazovians.
Some people called described "tribe" (Old Podlachians)