The Monument was the project of Lt Colonel Joaquim da Costa Cascaes and was constructed on the orders of the Marquis Sá da Bandeira. Its construction was approved at the end of August, 1874 and work started the following year. It was completed in 1883. The statue (the classical Greek figure of Hercules) has three of his best-known attributes: his beard, lion’s skin and stout staff. The sculptor was Simões de Almeida and the marble was quarried at Pêro Pinheiro.
This monument, erected on a viewpoint over the town of Alhandra, commemorates the victory of the Anglo-Portuguese troops over the Napoleonic armies, as well as the construction of the Lines of Torres Vedras.
In 1911, two plaques were added in honour of the military engineers involved in this extraordinary mission: Lt Colonel Sir Richard Fletcher of the English army and Neves Costa, an officer in the Royal Portuguese Corps of Engineers, whose studies of the terrain gave rise to the Lines.