The fortress of the Castro was built in 1665 during a war in front of Portugal (1640-1668) trying to protect the city from the continuous attacks coming from the British navy allies of Portugal. The defensive system of the city consisted in Castro and San Sebastián fortress and the city wall (now disappear). The city wall had an irregular structure because of the orography, it was constructed by the Engineer Colonel Fernando de Gourannanbergue and the Field Master Diego Arias Taboada to unify the two fortresses. Despite of this effort to provide security to the city, Documents from that time say that this defensive system was not so effective because it can not stop landings.