The Jatvings, closely related to the Old Prussian, Lithuanian and Latvian tribes, belonged to the Baltic branch of the Indo-Europeans who, in the 5th century BC, migrated north up the Driieper river to settle the southeast coast of the Baltic Sea. (Die Balten 1987: 18, 20). On the evidence available, Jatvingia as a complex of tribal communities emerged in the second half of the 1st millennium AD. The historical home of the Jatvings was in the northeastern corner of modern Poland and in the adjacent parts of modern Lithuania. It stretched eastwards across the Masurian Lakeland to the river Neman, touching on the Biebrza river valley in the south and the upper Sheshupa valley in the north (FIGURE 1). Information on Jatvingians survives in early mediaeval written sources: Polish documents, the chronicles of the Ruthenian Dukes and the Teutonic Order, Papal Bulls, etc. Interestingly enough, one of the oldest mentions in western European sources comes from an English source – the Otia imperialia written by Gervase of Tilbury.