[2] The buildings of the current castle date back to Sancho Sánchez de Ulloa (1442–1505), 1st Count of Monterrey, who built the 22-metre high keep, the "Torre de Don Sancho", in 1482,[3] although the castle's other keep, the "Torre das Damas" (19 metres), was possibly built earlier.

[1] In the early stages of Marshal Soult's Second French invasion of Portugal, the Spanish General La Romana had set up the headquarters of his Army of Galicia, numbering some 9,000 troops, at Monterrei where, at the Battle of Monterrey (6 – 7 March 1809), the French army the routed the Spanish forces.

Still in Spain, this was the first point where there was a bridge over the river,[5] but Soult knew that before penetrating the Portuguese border he would have to eliminate the threat of the Spanish forces stationed there.

[6] Following the rout of La Romana, Soult stayed on at Monterrei for three days waiting for his rearguard and his convoy of sick to join the main body of his forces,[5] and then crossed the Portuguese frontier between Monterey and Chaves on 9 March,[5] and headed towards Porto, laying siege to Chaves, which he captured on 12 March 1809.

[7] However, in 2016, the High Court of Justice of Galicia confirmed the annulment of the planning permission the Council of Monterrei had previously given for converting the castle into a hotel.