Eastern Baltic in the context of "Selonians"

The Selonians (Latvian: sēļi; Lithuanian: sėliai, from Livonian: sälli – "highlanders") were a tribe of Baltic peoples. They lived until the 15th century in Selonia, located in southeastern Latvia and northeastern Lithuania. They eventually merged with neighbouring tribes, contributing to the ethnogenesis of modern Latvians and Lithuanians. They spoke the Eastern Baltic Selonian language.