Termantia, now known as Tiermes, is an ancient site located on the edge of the Duero valley in Spain. It is found in the town of Montejo de Tiermes, which is part of Soria in the region of Castile and León.

During the Iron Age, Termantia was a hill fort built by the Celtiberians. It fought against the Romans and was allied with Numantia during the Celtiberian Wars. It is believed that the Romans granted it the status of a municipium. The original name was changed by the Romans to Termes or Termantia. The site is notable for its location on a dry, red sandstone hill and for the buildings that were carved directly into the rock.

Roman history

Termes became wealthy during Celtiberian and Roman times, possibly because of sheep farming. Evidence suggests that flocks were moved yearly between the northern plateau and Extremadura. The area also had deposits of iron and other metals.

The Roman conquest of the Iberian Peninsula took about 200 years. A key event was the Celtiberian Wars, which led to the addition of much of Celtiberia up to the middle of the upper Duero after Numantia fell in 133 BC. During this time, Termes was attacked by the Roman consul Q. Pompey in 141 BC. In 139 BC, Pompey signed a treaty with Termes and Numantia. However, the Roman Senate later changed the treaty. Fighting continued, but Termes was not directly affected. By the end of the 2nd century BC, Rome restarted the conquest beyond Numantia. Termes fell in 98 BC after the consul Titus Didius attacked the city. He forced the people to move to the plain, a change that lasted about one or two decades. After this, Termes paid tribute to Rome (civitas stipendaria), beginning a slow process of becoming more Roman.

Starting in 70 BC, the city began major changes, using the three levels of the hill, especially the middle level, where important buildings would later be built.

The city was likely given the title Municipium during the reign of Emperor Tiberius. Termes was placed in the Conventus Cluniensis, and the Roman city began to develop. Its most prosperous period was between the first and second centuries AD. The city had large public buildings, two markets (one from the Julio-Claudian period and another from the Flavian period), thermal baths, a possible theatre, an aqueduct, and urban planning suited to its location on a sandstone bluff surrounded by river gorges and forests.

A special feature of Termes, and one of its most impressive sights today, is the method of carving buildings directly into the rock. This technique was later improved with Roman construction methods. The city has many remains of buildings with this style, including private homes (like the House of the Niches and the Aqueduct House) and public structures (such as rock bleachers and a theatre), as well as infrastructure like aqueducts, drainage systems, and pathways.

The construction of a wall in the late 200s AD shows that the city kept its unique features for at least until the middle of the 4th century AD. Termes declined during late antiquity.

Post-Roman history

Not much is known about the city's history during the Visigothic and Islamic times. There is a Romanesque church in the area. Because the region is now mostly empty, the church is classified as an eremita, which means a hermitage.

Archaeology

The archaeological remains are located on several terraces and in the southern plain:

Flight of steps carved into the rock: a large public area with unknown purpose and age. The steps are divided into sections, with stairways leading to the door of the Sun, one of the ancient city entrances. Southern rock complex: remains of homes likely built during the Celtiberian era. These homes were carved into the rock on two levels, with the front walls built during the Roman era. There are 11 houses divided into two areas, separated by a staircase. Among these, the "house of the Niches" also has an upper floor. Canal aqueduct: a water channel carved into the rock that brought water from the hill to the Roman city. Part of the aqueduct was underground. West Gate: a pedestrian entrance to the city. "House of the aqueduct": a residence covering 1800 square meters with 35 rooms on different levels connected by stairs. The foundation was built into the hill, and the walls were covered with plaster and decorated with murals. Forum: an area with a temple dedicated to the imperial cult, an arcaded square, and a macellum with taverns.

In 2018, a geophysical survey using Magnetometry identified new housing areas within the city walls and previously unknown structures outside the city’s supposed boundaries, located at the far west and far east of the hill. The western structures are believed to be older than the Roman city of Termantia/Termes, part of an Iron Age hilltop settlement. The eastern structures have no fixed time period and may belong to a previously unknown part of the Roman settlement.

Conservation and Museum

The site is protected by Spanish law and is listed as a Zona Arqueológica. A museum is located at the site, which is a branch of the Numantine Museum of Soria. The Friends of the Tiermes Museum (Asociación de Amigos del Museo de Tiermes – AAMT) is a nonprofit organization established in 1988. AAMT focuses on protecting the environment and supporting sustainable tourism.

The European LIFE Programme provided funding between 2003 and 2006 to help develop eco-cultural tourism in an area with few economic opportunities. Projects were carried out to preserve and improve both archaeological and natural heritage. The initiative identified the possibility of designating a Special Protection Area for birds. The area is also home to wolves. Encinares de Tiermes, a Site of Community Importance, was designated a Special Area of Conservation for its species in 2015.

Activities available at Tiermes include guided tours and dark sky astronomy. Dark sky astronomy is also promoted in Borobia, another sparsely populated location in the province of Soria.