The Paderne Castle is a Hisn, small rural fortification, founded by the Almohad in the 2nd half of the twelfth century. The defensive system was equipped with a barbican tower with quadrangular, which still retains with a height of 9 m. Inside the castle, the archaeological excavations exhumed housing structures, demonstrating that, under the walls, the space was completely urbanized with narrow streets but orthogonal layout, covered by a complex system of drains that lead waste water to the outside of the enclosure fortified. The streets formed blocks, with a specific density of occupation of urban contexts of the Islamic era, with central courtyard housing characteristics discovered which was acceded from all rooms. After the Christian conquest of the Algarve settled in the castle a new population, who adapted or changed with different concepts, the initial domestic model. Two cisterns give testimony of the two main castle occupancy times - Islamic and Christian.