The Fort of Graça was built by D. José I, on the hill where the old chapel of Nossa Senhora da Graça was located. Monte da Graça is one of the highest points in the region, therefore constituting a place of great strategic importance. During the siege of Elvas (1658-1659), in the context of the War of Restoration, the Spanish army took the place and installed an artillery position there, from which it severely attacked the city. The situation was repeated in 1762, during the Seven Years’ War (1756-1763), when Elvas was again under siege. Finally, and as early as 1763, D. José I ordered the construction of a fortress that would complete the city’s defensive circuit. Its planning was commissioned by Marshal Wilhelm von Schaumburg-Lippe, better known as Count de Lippe, who had come from England the previous year,
The chapel of Santa Maria da Graça was destroyed, having the image of the Virgin who guarded moved to the chapel of the fort, where it came to disappear later with the French invasions. The work was very demanding for the region, having worked from 3 to 4 thousand men between 1763 and 1792. The fort was immediately known as Fort de Lippe, and later, in 1777, by order of D. Maria I, for Fort of Nossa Senhora da Graça. The building withstood the attack of Spanish troops during the War of Oranges (1801), and the bombardment inflicted by French troops of General Soult, in the context of the Peninsular War (1811).
The fort is a masterpiece of 18th century European military architecture, both for the originality of the solutions presented there, and for its monumentality. It consists of three lines of defense. The outermost work consists of a covered path, defended by cannons, a hornaveque (from the German hornwerk ), composed of two half-bulwarks connected by a curtain, and by a dry moat, 10 meters wide. There follows a quadrangular structure with 150 m on the side, with four bastions at the vertices. The wall cloths, or curtains, are covered by revelins and torn by the main door, called Porta do Dragão , in the south, and by “posterior doors” or poternas, protected by cannons. Between the curtains and the second moat there are numerous outbuildings, including barracks and other buildings. The stronghold itself is an octagonal tower, with vaulted floors, consisting of a chapel on the ground floor and Casa do Governador on the noble floors. Below the chapel there is a notable cistern. The stronghold is defended by three orders of batteries in casemates, with gunboats. SML