The Castle of Almourol is a medieval castle atop the islet of Almourol in the middle of the Tagus River, located in the civil parish of Praia do Ribatejo, from the municipal seat of Vila Nova da Barquinha, in Portugal's Oeste e Vale do Tejo region. The castle was part of the defensive line controlled by the Knights Templar, and a stronghold used during the Portuguese Reconquista.
History
235px|left|thumb|A view of the [[Tagus|Tagus River from the castle, showing the granite outcropping and its 18-metre rise over the waterway.]]
It is believed that the castle was constructed on the site of a primitive Lusitanian castro that was later conquered by the Romans during the 1st century B.C.E. It was later remodeled by successive invading forces, including the Alans, Visigoths and the Arabs, although it is unclear when the present castle was established. The structure was reconstructed, starting in 1171 (from an inscription over the principal gate) and restored during the subsequent reigns. Similarly, the watchtowers were innovations brought into the western Iberian peninsula by the Templars, and applied in Almourol.