This hill fort was built by the Moors in the second half of the 12th Century. Its is approximately 8 kilometers (5 miles) from the Algarve resort of Albufeira. It is situated on a bend on the River Quarteira close to the village and civil parish of Paderne. It is 7.5 Km (4.7 miles) North from the coast.

The castle is one of the seven castles that are represented on the national flag of Portugal. Its location on a rocky peninsular bend in the river was of huge strategic importance to the Moors as it controlled the ancient roman road ‘Via Lusitanorum’ that crosses the river Quarteira on the southern side of the castle. The Roman Bridge still stands at the crossing point below.

The castle now mainly in a ruinous state is almost a hectare in size and has the perimeter footprint of a trapezoidal shape. The eastern side, which has the least natural defence has a substantial tower and is built of Taipa (Mixture of mud, chalk, lime and aggregate that sets like concrete). This tower, the only one left standing in the enclosure, protrudes from the wall and is connected to the main fortification by an upper passageway. On the outside of this tower it is still possible to make out the whitewash strips which were applied to the joins of the layers of taipa to give the impression that the tower was built from masonry. Nevertheless these mud walls are still 1.8 meters thick and are constructed on a substantial stone plinth which can be seen at the base of the perimeter walls. There are also at intervals, vertical openings to allow for drainage of any accumulative water inside the castle walls.

Below the tower can be seen the remains of ramparts which ran across the eastern perimeter but most of it has collapsed, probably at the time of the earthquake of 1755. This rampart which is lower than the main walls also defended the main Gateway to the castle, which is at a right angle to the main wall which created an ‘L’ shaped entrance designed to make any frontal attack that much more difficult. Not all the stonework in the entrance way is original, being replaced and made safe during restoration work. In side the precinct of the castle can be seen the remnants of a cistern.

On the south wall are the ruins of the former chapel of Nossa Senhora do Castelo which was the Parochial church for the nearby village and date from the 14th century. The church was abandoned by the residents of Paderne in 1506 when a new parochial church was built in the village. In 2002 archaeological digs of the castle precinct have brought to light evidence of dwellings and streets within the castle compound and the discovery of the remains of a sophisticated sewerage system and vestiges of the network for the cisterns and channels for the collection and supply of drinking water. Paderne Castle was, in fact, a fortified village and predates the foundation of today’s town of Paderne, possibly by as much as two centuries.