Rapitán fort is one of the most interesting elements of the vast military heritage that is spread throughout the Jacetania Area. It was conceived at the end of the 19th century as a part of the dense defensive network that was intended along the international Oloron-Canfranc railway line. The relatively fresh memory of the War of Independence, the demands made by the Ministry of War as part of the Canfranc project, and the ancestral fear of invasion from the other side of the mountain range all help to explain the historical context in which these works were planned.

The first stone of the Rapitán castle was laid in 1884. The chosen spot left little doubt. Placed at the entrance to the valley traversed by the River Aragon, at the top of a mountain of the same name that dominates the entire Jaca plain, it was of guaranteed importance in the defense of the national frontier. Since 1675 the mountain had been used by the town of Jaca for grazing. The fort was built at the same time as the “Coll de Ladrones” fort in Canfranc and the Santa Elena fort in Biescas.

The access track was finished two years after the start of work and in 1890 the first eleven artillery pieces arrived from the Trubia foundry to arm the castle. In order to overcome the difficult terrain and facilitate access for building materials and heavy armament a 37-metre long hemp rope was made that weighed more than 200kg. Hundreds of labourers worked for two decades to build the fort, thereby saving many families from the desperate state of poverty that they found themselves in. Rapitán was finished in 1904, and garrison activity started immediately, although it soon became apparent that advances in military tactics and strategies were rapidly to make it obsolete. During the Civil War the moats were the dramatic stage on which the rearguard action was fought, while during the Franco period activity at the fort steadily declined until it was finally abandoned.

Since 1973 the fort is administered by the City Council of Jaca, although it remains the property of the Treasury Ministry. In 1978, work was undertaken to convert it for residential and cultural uses, for which it continues to be used from time to time.