Its name combines two terms, base and complement, which are characteristically frontier terms; the toponyms Salvatierra usually refer to localities which, during the Reconquest, were used to defend the frontier. Erected as fortifications in frontier territory, the people who arrived there undertook to defend it, while benefiting from certain privileges and the protection of the king. This defensible frontier was not necessarily the boundary between Christians and Muslims; it was also the boundary between Christian kingdoms, as, in fact, that was the situation both of the one we find here and of the Galician Salvatierra de Miño -gall. Salvaterra de Miño-. Something similar can be said of the complement Extremo, which is the name itself of what until 2013 was a Portuguese parish bordering on Galicia, today joined to Portela, and which we also see as the basis of the coronym Extremadura.