The São João Baptista Fort is located on the Ilha das Berlengas, in Peniche, and was built in 1651, by order of D. João IV, and completed in 1656.
Built in order to prevent the occupation of this island by North African privateers or by enemy powers, in June 1666 it experienced the most celebrated war episode in its history. On that date, the Forte de São João Baptista was besieged by a Spanish fleet, composed of fourteen ships and a caravel, commanded by D. Diogo Ibarra. Defended, at the height, by a small garrison, less than twenty men, and with only nine pieces of artillery, this fortification led by Corporal Avelar Pessoa, managed to resist for two days the ferocious enemy bombardment, as well as causing important casualties in the surrounding forces, translated into about five hundred dead, one sunken ship and two others heavily damaged, against one dead and four injured Portuguese. The exhaustion of supplies and ammunition, and the desertion of one of the soldiers, who exposed D. Diogo Ibarra to the dramatic situation of the Portuguese garrison, finally motivated the capitulation of the Fort of São João Baptista.
National Monument, the Fort currently functions as a shelter (managed by the Association of Friends of Berlengas), offering guests a unique opportunity to rest, with the company of silence, only broken by the crash of the waves and the singing of the pardelas at the end pm.
