The largest bulwarked dry-ditch system in the world
Elvas Travel Blog› entry 65 of 113 › view all entries
The Elva site, extensively fortified from the 17th to 19th centuries, represents the largest bulwarked dry-ditch system in the world. Within its walls, the town contains barracks and other military buildings as well as churches and monasteries. While Elvas contains remains dating back to the 10th century ad, its fortification began when Portugal regained independence in 1640. The fortifications designed by Dutch Jesuit padre Cosmander represent the best surviving example of the Dutch school of fortifications anywhere. The site also contains the Amoreira aqueduct, built to enable the stronghold to withstand lengthy sieges.
Guarding the key border crossing between Portugal’s capital Lisbon and Spain’s capital Madrid, in an undulating, riverine landscape, the Garrison Town of Elvas was fortified extensively from the 17th to the 19th centuries to become the largest bulwarked dry ditch system in the world, with outlying forts built on surrounding hills to accommodate the changing needs of defensive warfare.
The town was supplied with water by the 7km-long Amoreira Aqueduct, built in the late 16th and early 17th centuries and a key feature enabling the stronghold to withstand a lengthy siege. Within the walls, the town contains extensive barracks and other military buildings, as well as churches and monasteries, some adapted to military functions. The property includes seven components: the Historic Centre, the Amoreira Aqueduct, the Fort of Santa Luzia, and the covered way linking it to the Historic Centre, the Fort of Graça, and the Fortlets of São Mamede, São Pedro and São Domingos.
The historic centre with its castle, remnant walls and civil and religious buildings demonstrate the development of Elvas as three successive walled towns from the 10th to the 14th century and its subsequent incorporation into the major fortification works of the Portuguese War of the Restoration period (1641-68), when a wide range of military buildings were built for its role as a garrison town.
The bulwarked fortifications of the town and the outlying Fort of Santa Luzia and Graça and fortlets of São Mamede, São Pedro and São Domingos reflect the evolution of the Dutch system of fortification into an outstanding dry-ditch defence system.
These surviving fortifications were begun in 1643 and comprise twelve forts inserted in an irregular polygon, roughly centred on the castle and making use of a landscape of hills. The bulwarks are battered, surrounded by a dry ditch and counterscarp and further protected by a number of ravelins. The fortifications were designed by the Dutch Jesuit Cosmander, based on the treaties of fortification engineer Samuel Marolois, whose work together with that of Simon Stevin and Adam Fritach launched the Dutch school of fortification worldwide.
In the 18th century the Fort of Graça was constructed in response to the development of longer-range artillery, as well as four fortlets to the west.
As the remains of an enormous war fortress, Elvas is exceptional as a military landscape with visual and functional relationships between its fortifications, representing developments in military architecture and technology drawn from Dutch, Italian, French and English military theory and practice. Elvas is an outstanding demonstration of Portugal’s desire for land and autonomy, and the universal aspirations of European nation States in the 16th-17th centuries.