It was built after the Carlist War of 1872-1876 because Carlists succeeded to reach Pamplona -controlled by the liberal Government- with their artillery from this and other mountains surrounding Pamplona from the north. The advances in artillery during late 19th century forced the military authorities to build this kind of fortifications in order to control mountains and hills close to important towns. Another example of this is the fort San Marcos, near San Sebastián.