The two uninhabited islands of Gramvoussa, Agria (Wild) Gramvoussa and Imeri (Tame) Gramboussa, are located opposite the imposing Gramvoussa Peninsula, about 20km north-west of Kissamos.
The castle is built on the steep, flat rise of the islet Imeri Gramvoussa, in the framework of a wider fortification project of Crete, at the end of the Venetian rule. Its construction started in 1584, with the designs and the supervision of Latino Orsini.
The castle covered an extensive area. It included underground reservoirs for collecting the rain water, foundations of buildings, the church of the Annunciation and the gunpowder warehouse, which was transformed into o mosque during the Ottoman rule. The shape of the fortress is irregular as it has walls and bastions on three of its sides, while in the north it is protected by inaccessible rocks.
The fortress was occupied by the Ottomans in 1692, because of treason. It remained in their possesion until the Revolution of 1821, when rebels occupied it. Then, was occupied again by the Ottomans and remained abandoned until recently, when restoration works, were started.
From the remaining buildings, the church of the Annunciation and the gun-powder warehouse are preserved while the headquarters, the barracks and other facilities can also be seen.
