Miróbriga

Mirobriga or Mirobriga of the Celts (Mirobrigensis qui celtici cognominantur - Plin. Nat. IV 118) was an ancient town in the westernmost part of Lusitania during the Iron Age and Roman Times that was mentioned by Pliny the Elder and Ptolemy.

Despite some debate, the city is generally associated with the archaeological site of Castelo Velho de Santiago do Cacém (Herdade dos Chão Salgados) located near the village and civil parish of Santiago do Cacém, in the municipality of the same name in the south-west of Portugal.

The ruins were first mentioned by André de Resende in the 16th century, who also made the association with the toponym. The site is also known as Roman ruins of Mirobriga and Roman city of Mirobriga.

Archeology revealed that the site has been occupied since the Iron Age, at least since the 5th/4th century BCE, but possibly going back to the 9th century BCE, by Proto-Indo-Europeans.

With the Roman colonization came the need to administrate the new incorporated territories. As such, in some cases cities were created anew while in others, existing indigenous settlements were transformed to meet the requirements. The original settlement developed into a city in Roman times, and was occupied until the Early Middle Ages.

The Forum occupied almost the entire area of the previous settlement, and around it a commercial area was developed.

The two Balneae or Thermae, set side-by-side, are among the best preserved in Portugal. Several domestic buildings have been identified in the last decades, mostly consisting of peristyle houses.

Relatively close to the baths, there is a bridge with a single arch.

The Circus, the only one whose entire ground plan is completely known in Portugal, is located further from the centre, approximately 500m to the south.