It was built by the Spanish governor of Milan, Don Pedro Enríquez de Acevedo, Count of Fuentes, to command the Pian di Spagna and the strategic Trivio di Fuentes, the crossroads between the Valtellina, the Valchiavenna and the Alto Lario, in order to defend the northern border of the Spanish domain against the Grisons to the north.

Construction was begun in 1603[1] or October 1609[2] under military architect Gabrio Brusca, and was substantially complete within three years.

Like the city of Milan, the fort of Fuentes yielded in 1706 to Prince Eugène of Savoy, ending Spanish control of the area.

The fortress was largely demolished in 1796 by general François Rambeaud [fr] on the orders of Napoleon and at the request of the Grisons.

From 1911 until 1913 the Fort Montecchio-Lusardi with eight gun emplacements were constructed on the site, and the circular Spanish tower on the western side demolished at this time.