The Caristii are first mentioned by Roman sources; Pliny the Elder names them Carietes and places them in the Basque interior territories, what today is the southernmost regions of the Basque Country, while Ptolemy places them between the river Deba and Nervión, present-day provinces of Biscay and Gipuzkoa, with a territory triangle-shaped, reaching the city of Vitoria by the south.