Latgalians

Latgalians, sometimes also Ancient Latvians (Latin:Lethi, Letthigalli, Low German:Letti, Lethi, modern Latvian:latgaļi, letgaļi, leti, variant translations also include Latgallians, Lettigalls or Lettigallians) were an ancient Baltic tribe.

They likely spoke the Latvian language, which probably became the lingua franca in present-day Latvia during the Northern Crusades due to their alliance with the crusaders. Latgalians later assimilated the neighboring tribes, forming the core of modern Latvians.