The ruins of the old Roman city of Clunia Sulpicia,
one of the greatest and most important towns of Roman Spain can
be found near Peñaranda de Duero and in the district of
Peñalba de Castro.
Before the arrival of the Romans, Clunia was a native settlement for the Arevacus, a lineage of the Cantabrians and Vascons. Tiberius founded a roman "municipium" here and later, in the times of the emperor Galba or Adrian, it obtained the rank of Colony, "Colonia Clunia Sulpicia". It was the capital of one of the legal Convents of the Citerior or Tarraconense Hispania, Sertorius resisted Pompeyo here, in the year 72 b.c. Here, in the year 69 a.c. Servius Sulpicius Galba was proclaimed emperor of Rome.
The city, seated on a meseta, reached 30,000 inhabitants at one time. Proof of its ancient splendour is the theatre excavated in the rock, with a capacity for 9,000 spectators, the thermal baths of "Los Arcos", with 7,000 square metres, the forum where the temple devoted to Jupiter and the courts of justice were raised, as well as the magnificent mosaics discovered in many of the ancestral homes.