The Roman bridge at Alcántara in Extremadura, Spain, is one of the finest examples of Roman bridge-building and a monumental feat of engineering. It was built over the Tagus River in the ancient Roman province of Lusitania between 104 and 106 AD. It was dedicated to the Roman emperor Trajan on behalf of the local indigenous populations. Built of granite and without mortar, the Alcántara Bridge consists of six semicircular arches supported by five pillars. It spans the river at almost 200 m and rises more than 40 m meters above the water level. The architect of this great masterpiece was a man called Caius Julius Lacer.
The name of the bridge comes from the Arabic “El Kantara”, meaning “bridge”. Its dimensions make it unique among Roman bridges, and it boasts the largest arch span of the peninsular Roman bridges, with an arch of almost 29 m. At its ends, the arches are supported by buttresses.
An honorific arch at the centre of the bridge was dedicated to the emperor Trajan. The inscription found on the attic reads (CIL II 759): Imp(eratori) • Caesari • divi • Nervae • f(ilio) • Nervae / Traiano • Aug(usto) • Germ(anico) • Dacico • pontif(ici) max(imo) / trib(unicia) • potes(tate) • VIII • imp(eratori) • V • co(n)s(uli) • V • p(atri) • p(atriae).
Another inscription from the side of the triumphal arch reveals that the bridge was paid for by eleven Lusitanian municipalities (municipia provinciae Lusitaniae). The inscription also claims that, in addition to contributing funds to the building of the bridge, these local municipalities ‘completed’ the bridge (perfecerunt).
At the southeast end of the monumental bridge are the remains of a small votive temple, distyle in antis, of Tuscan order with a single cella. It was constructed as an offering to Trajan and the gods of Rome. It was designed by the same architect as the bridge and the triumphal arch, Gaius Julius Lacer. The dedicatory inscription (CIL II 761) on the temple (now a reconstruction of the original), cut in a slab of marble, records that the temple was dedicated to Trajan, erected by the bridge’s architect Gaius Iulius Lacer, with the help of his associate and friend Curio Lacone Igaeditano (from the city of Idanha-a-Velha). After the conquest of Cáceres in 1169 by Ferdinand II of Leon, the temple was converted into a chapel of St. Julian, which explains why the building remains so well-preserved. The architect was buried in the temple, and his tomb is still preserved inside.
pontem perpetui mansurum in saecula mundi (a bridge that would last forever)
Over the centuries, the Alcántara Bridge sustained damage in various armed conflicts and environmental events, mainly water-related, which have led to the destruction of part of its structure and degraded it. The bridge was restored during the reign of Isabel II by the engineer Alejandro Millan y Sociats in 1859. It was listed as a Spanish National Monument in 1924 and is in the process of being declared a World Heritage Site by UNESCO.
Coordinates: 39° 43′ 21.00″ N 6° 53′ 33.00″ W