One of the best preserved ancient Roman road networks is to be found in the Roman Province of Lusitania (including approximately all of modern Portugal and part of modern Spain) with numerous cobbled streets and an amazing amount of well-preserved bridges. I visited many of those bridges as part as my archaeological trip to Portugal in February 2014, mainly in the central and southern part of the country (I did not explore northern Portugal).
The Roman Province of Lusitania was founded by Emperor Augustus in 27 BC and its capital was Emerita Augusta (Mérida, Spain). Between 28-24 BC Augustus’ military campaigns pacified all Hispania under Roman rule, with the foundation of Roman cities like Asturica Augusta (Astorga) and Bracara Augusta (Braga) to the north, and to the south Emerita Augusta.
The Roman road network in Portugal is the largest engineering performance from Antiquity in Portugal. Many remains of Roman roads with well-preserved pavement are still visible and a variety of very well-preserved bridges. Ancient bridges are not always possible to identify as Roman and may in some cases be Medieval constructions built in the Roman style. However the bridges mentioned here have been asserted to be Roman.
A major road from Olisipo (Lisbon) went north to Scallabis (Santarém) and on to Sellium (Tomar), Conimbriga, Aeminium (Coimbra) and to Bracara Augusta (Braga). Another important road connected Myrtilis Iulia (Mértola) with Pax Iulia (Beja) and Ebora (Évora) to the North. From the Roman capital at Emerita Augusta it was possible to reach Olisipo via the road to Ebora then to Salacia (Alcácer do Sal)
Of the numerous Roman bridges in Portugal, the most outstanding is that of Vila Formosa, a 116 metre long bridge spanning over the river Seda.
This bridge, dating back to the late 1st century / early 2nd century AD, is one of the best preserved bridges throughout the Iberian Peninsula. It was located on the road which connected Olisipo (Lisbon) to Augusta Emerita (Mérida, Spain), the via publicae. It is built in thick cut stonework and granite panels (opus quadratum). It has six complete arches, all of them of the same size and composed of 33 intrados, which form quadrangular abutments. Between the arches on top of the pillars Ponte de Vila Formosa has five complete vaults archway.
Another good example of Roman engineering is the Roman bridge of Segura (Ponte Romana de Segura) built in the early 2nd century AD under Trajan on the route that linked Augusta Emerita and Egitania (Idanha-a-Velha). It consists of five arches barrel vault, the three central ones, having been rebuilt in the sixteenth century by Portuguese masons. The Roman bridge of Segura now connects Spain with Portugal.
The Ponte da Ladeira dos Envendos was part of the Roman province road that linked Aritium Vetus (Alvega) to Salmantia (Salamanca, Spain). The ancient bridge over the river Ribeira da Pracana is about 40 meters long and has six arches of different spans. Ponte da Ladeira dos Envendos was built between the 1st century BC and 1st century AD.
The Ponte de Vila Ruiva, spanning the river Odivelas near Cuba in the District of Beja, belonged to the ancient Roman road which connected Ossonoba (Faro) and Pax Iulia (Beja) bound for Ebora (Évora) and Augusta Emerita. Ponte de Vila Ruiva presents several construction phases. It is assumed that the original structure, made of granite, dates back to between the 1st century BC and 1st century AD. Reconstructions on the bridge were undertaken in the 5th century and 11th century using ancient and new materials. Ponte de Vila Ruiva is still in use today.
The Ponte dos Três Concelhos, spanning the river Ribeira de Isna, is a three-arched Roman bridge. This bridge was part of a Roman road that connected Augusta Emerita (Merida, Spain) to Conimbriga. It was probably built between the 1st and the 4th century and rebuilt between the 13th and the 14th century.
On the banks of the river Pônsul, ca. 50 km from Castelo Branco, the Roman town of Igaeditania (Idanha-a-Velha) became a municipium in the time of the Flavians. A road from Augusta Emerita to Igaeditania run across the Roman bridge crossing the Pônsul which seems to have been constructed in 5 or 6 AD, when Augustus set the limits of the civitates of the region. Igaeditania was thus an important road centre. The bridge was reconstructed several times across the centuries. What we see now is mainly the result of a reconstruction from Middle Ages.
At Mirobriga Celticorum, a Roman town located south-west of Portugal near the coast, lay a small single-arch bridge that provided access along the west-east road leading to the forum and the Imperial temple of the Roman town. The bridge was made of irregular limestone, opus incertum. The original paving of the bridge is still visible.
In Mértola (Roman Myrtilis), an important ancient port on the River Guardiana, stand the remains of imposing piers of a bridge lined up in the late Roman period to give access to a River Tower. The tower controlled one of the most important entries into the city. An access route, built on a solid series of arches, allowed the tower to connect with the interior of the City Walls.
Here is a map of all the Roman bridges covered here. Of course there are more bridges to look for in Portugal, especially in the northern part of the country which I hope to explore soon.