The Lines of Torres Vedras were a line of forts in Portugal built in secrecy between November 1809 and September 1810 during the Peninsular War. The Lines were ordered by the Duke of Wellington and constructed by Portuguese workers, under the supervision of British and Portuguese Army Engineers. The fortifications take their name from the town of Torres Vedras.

Genesis

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After his troubling Spanish experience at the Battle of Talavera de la Reina, Wellington decided to strengthen Portugal. He used a report of Colonel Vincent, ordered by Junot in 1807, describing the excellent defensive capacities in the region nearby Lisbon and topographical studies by Major Neves Costa. He was also inspired by the Martello Towers along the British Channel coast. Wellington ordered the building of the Lines of Torres, as a system of fortifications blockhouses, redoubts, ravelins, cuts of natural relief, etc. The work began in the Autumn of 1809 and the first line was finished one year later. Construction of the lines continued and in 1812 34,000 men were still working on them.

The work was supervised by Colonel Fletcher, assisted by Major John Jones, 11 British officers, 2 KGL officers and 4 Portuguese Army engineers. The cost was down to around £100,000, one of the less expensive but remunerative military investments in history. The human cost was great for the population, because of the privations they supported. It is estimated that between October 1810 and March 1811 about 50,000 Portuguese died of hunger or disease.

The Anglo-Portuguese army was forced to retreat to The Lines after the Battle of Buçaco. The French (under Marshall André Masséna) discovered upon their arrival at The Lines a barren land (under the Scorched Earth policy) and an enemy behind an impenetrable defensive position.

Masséna's forces arrived at the Lines on 11 October and shortly afterwards stormed Sobral de Monte-Agraco but were repulsed in the attempt to assault of Fort Alqueidao, a second bigger and better equipped redoubt. After attempting to wait out the enemy, Massena was forced to order a French retreat to Spain, starting on the night of 15 November 1810, to re-supply and reinforce his army. Marshal Masséna began his campaign with his army (l'Armée de Portugal) at 65,000 strong. By the time he reached Torres Vedras, he had 61,000 men (after losing 4,000 at the Battle of Buçaco). When he reached Spain, he had lost 25,000 men (including those lost at Buçaco). One of the coldest winters Portugal had ever seen hit Portugal and killed many of the French. They were also hit by severe illness and disease killing the soldiers in their thousands. The Allies were reinforced by fresh British troops in 1811 and renewed their offensive. They left The Lines and did not return for the rest of the Peninsular War.

Description

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The four lines of Torres Vedras had forts strategically placed in the top of hills, controlling the roads to Lisbon and using the natural obstacles of the land. The first line, with an extension of 46 km, binds Alhandra to the estuary of the Sizandro River. The second line, 13 km to the south, has 39 km and binds the Póvoa de Santa Iria to Ribamar. The third line consisted of a defensive perimeter with 3 km, from Paço de Arcos to the Tower of Junqueira, protecting a beach of embarkment (St. Julian's) about 40 km to the south of the second line.

In seven months, 108 forts and 151 redoubts were built, with ravelins, detached batteries, etc. The three lines were furnished with 1,067 pieces of artillery and provided with 68,665 men, one of the most efficient systems of field blockhouses in military history. Behind them was the field army of 50,000 Anglo-Portuguese regulars, able to manoeuvre against the invaders.

The fourth line was built south of the Tagus in the Altos of Almada to hinder an eventual invasion coming from south, with an extension of 8,000 yards (7.3 km): It had 17 redoubts and covered trenches, 86 pieces of artillery, defended by marines, and orderlies of Lisbon, for a total of 7500 men.

Substantial portions of the Lines still survive today, albeit heavilly decayed.

Efficiency and cohesion

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The efficiency and cohesion of the Lines was based on 5 points:

1) Redoubts of artillery with Portuguese artillerymen, commanded by major-general José António Rosa, and specialized to fire into preset zones, where the enemy attack was expected; Both lines had more than 80 km. The first line had 534 artillery pieces.

2) Military roads to cover the rear of the lines and allowing an extraordinary mobility of forces. In September 1810, the field army had some 66,598 regular soldiers. Including the Ordenanças and Milicias, it had 77,690 men.

3) A Semaphore system introduced by the British navy allowing a message to be sent around the lines in 7 minutes; or from the HQ to any point in 4 minutes. The signal system had five stations:

• Redoubt n.30 close to the Ocean (Bridge of Rol)...
• The great redoubt of Torres Vedras (Fort St Vincent)
• Monte do Socorro close to Pêro Negro, Wellington’s headquarters
• Monte Agraço
• Alhandra, by the Tejo.

4) The secret - The building of the lines took, surprisingly, only 7 months. Lisbon became a peninsula defended by a most efficient system of blockhouses. Everything was preserved as a secret, whose maintenance is as surprising as the building of the lines. It is said that when Masséna was first confronted by the Lines, he asked his staff why they had not known about them in advance. "Wellington has made them", replied someone. Masséna shouted, "To the Devil with you! Did Wellington make the mountains?"

5) The scorched earth policy - North of the lines everything that could supply the invading army was collected, hidden or burnt. A vast tract of land was deserted and perhaps 200,000 inhabitants of the neighbouring districts of the lines were relocated inside the lines.

Napoleonic Wars | Buildings and structures in Portugal | History of Portugal | Military of Portugal | Forts

Linhas de Torres