The origin of Tarna is not completely known, especially because the town has many Jewish surnames. It's believed that it may be an area founded by Sephardim, although its strategic position as a passage between the Cantabrian Coast and the Meseta suggests that the place could have some kind of occupation from the Cantabrian Wars or even in the pre-Roman era. This possibility is supported by the fact that there are nearby Roman influences, such as Campo de Caso and Puente de Arco. Unfortunately, there is no archaeological evidence to confirm this.