 It is known through archaeological remains that the site now occupied by the town was inhabited from prehistoric times, which establishes the existence of a fort in the Coto Cividade as well as in Roman times, as in Pious neighboring parish are remains of Roman amphorae, various ceramic and bronze coins confirming the occupation.However, the finding of greater magnitude and Roman is the best proof that Mondariz-Balneario was Romanized, are remains of a Roman road near the stands, on or river Tea, Cernadela bridge, also of Roman origin.Tradition has it that in 1282 and in the chapel of San Pedro which is situated in this county, took place the marriage of King Diniz of Portugal to the Princess Isabella of Aragon, daughter of Peter III and later became known as Isabel of Portugal.