In the 5th and 6th centuries, they lived in the eastern part of present-day Vidzeme (west of the Aiviekste River), and later on in nearly all the territory of that region.
In the 11th century, Eastern Orthodoxy started to spread in Latgalian lands from Polotsk and Pskov.
Subsequently, between the 13th and 16th centuries, they gradually assimilated into the other Baltic tribes: the Selonians, the Semigallians and the Curonians.
The first large scale excavations took place in Ludza Odukalns Cemetery in Latgale (1890–1891), where 339 Late Iron Age burials were uncovered.
In the area of the Gauja river, two Latgalian cemeteries, Drabešu Liepiņas and Priekuļu Ģūģeri, have been excavated too.
Archaeological excavations have also been carried out on the hillforts of Ķente, Koknese, Sārumkalns, Tanīskalns, as well as on other Latgalian sites.