Alcántara Bridge
Coordinates	39°43′21″N 6°53′33″W / 39.7224°N 6.8924°W / 39.7224; -6.8924
Crosses	Tagus River
Locale	Alcántara, Spain
Heritage status	Listed as cultural heritage since 1921[1]
Characteristics
Design	Roman arch bridge
Material	Stone
Total length	181.7 m (596 ft)[2]
Width	8.6 m (28 ft)[2]
Height	45 m (148 ft)[3]
Longest span	28.8 m (94 ft)[4]
No. of spans	6
Load limit	52 t (57 short tons)[5]
History
Designer	Caius Julius Lacer
Construction start	104 AD
Construction end	106 AD
Location

The Alcántara Bridge (also known as Trajan's Bridge at Alcantara) is a Roman bridge at Alcántara, in Extremadura, Spain. Alcántara is from the Arabic word al-Qantarah (القنطرة) meaning "the arch". The stone arch bridge was built over the Tagus River between 104 and 106 AD by an order of the Roman emperor Trajan in 98.^[6]

The Alcántara Bridge has suffered more damage from war than from the elements over the years. The Moors destroyed one of the smallest arches in 1214 although this was rebuilt centuries later, in 1543, with stone taken from the original quarries. The second arch on the northwest side was then later destroyed in 1760 by the Spanish to stop the Portuguese advancing and was repaired in 1762 by Charles III, only to be blown up again in 1809 by Wellington's forces attempting to stop the French. Temporary repairs were made in 1819, but much of the bridge was destroyed yet again in 1836 by the Carlists. The bridge was rebuilt in 1860 using mortared masonry.^[6] And following completion of the José María de Oriol Dam, which allowed for the draining of the Tagus riverbed, the main pillars were completely repaired in 1969.

The bridge originally measured 190 m (620 ft) in length, which today is reduced to 181.7 m (596 ft).^[2] The clear spans of the six arches from the right to the left riverside are 13.6 m (45 ft), 23.4 m (77 ft), 28.8 m (94 ft), 27.4 m (90 ft), 21.9 m (72 ft) and 13.8 m (45 ft).^[4]

The bridge's construction occurred in the ancient Roman province of Lusitania. In Ancient Rome, the costs of building and repairing bridges, known as opus pontis ("bridge work"), were the responsibility of multiple local municipalities. Their shared costs prove Roman bridges belonged to the region overall, and not to any one town (or two, if on a border). The Alcántara Bridge was built at the expense of 12 local municipalities in Lusitania. The names were added on an inscription on the archway over the central pier.^[7]

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  Looking south, in the background the small temple with Lacer's grave
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  The entrance of the temple with the crypt of the Roman engineer

• List of Roman bridges
• Roman temple of Alcántara
• Alcántara Dam

• Brown, David J. (1993), Bridges, New York: Macmillan Publishing Company, p. 25, ISBN 0-02-517455-X
• Durán Fuentes, Manuel (2004), La Construcción de Puentes Romanos en Hispania, Santiago de Compostela: Xunta de Galicia, pp. 194–200, ISBN 978-84-453-3937-4
• Galliazzo, Vittorio (1994), I ponti romani. Catalogo generale, vol. 2, Treviso: Edizioni Canova, pp. 353–358 (No. 754), ISBN 88-85066-66-6
• Graf, Bernhard (2002), Bridges that Changed the World, Munich: Prestel, pp. 20–21, ISBN 3-7913-2701-1
• O'Connor, Colin (1993), Roman Bridges, Cambridge University Press, pp. 109–111 (SP21), ISBN 0-521-39326-4

• Alcantara Bridge at Structurae
• Puente de Alcántara sobre el Tajo, en Cáceres (in Spanish)
• Video of the bridge
• Video of Alcántara