The region of Silves has been inhabited since the Palaeolithic, as attested by archaeological remains, including several menhirs. The river Arade, which was navigable in historical times, linked the hinterland to the open ocean and allowed the transport of produce and commerce. The town of Silves (Cilpes) was possibly founded during the times of Roman domination, when the region was part of the Lusitania province.
After 713, when the Moors invaded Iberia, Silves became part of the Umayyad Emirate of Córdoba under the Arabic name of Shilb (شلب). In the 10th century it was one of the most important towns of western Al-Andalus. Silves became an independent taifa in 1027 under the rule of Ibn Mozaine and his son, who was dethroned in 1051 by al-Mu’tadid, the governor of Seville. al-Mu’tamid ibn ‘Abbad, the son of al-Mu’tadid and a famous poet, ruled the taifa of Silves until 1091. After the Almoravid conquest the town became Almohad in 1156. In 1189 King Sancho I of Portugal conquered the town with the aid of Northern European crusaders, but lost it again to the Almohads. Periodic raiding expeditions were sent from Al-Andalus to ravage the Iberian Christian kingdoms, bringing back booty and slaves. The governor of Córdoba attacked Silves in 1191, and took 3,000 Christian slaves. Again under Muslim rule, the city would then prosper to the point of being called the Baghdad of the West.
The town was finally taken from the last Muslim king Ibn Afan by Paio Peres Correia, Grand-Master of the Order of Santiago in 1242, after the Alentejo and most of the coast had already fallen in 1238. The great mosque was changed into Silves Cathedral(Sé Catedral). Silves declined in importance thereafter and was eclipsed in the region by Faro during the colonial period. In 1491, the town was given to queen Leonora by King João.
Parts of the Almohad town wall, constructed from poured concrete, have been preserved, as well as the Almedina-gate (Porta de Loulé). Other sights include the Santa Misericórdia Church with a fine door in Manueline style (the main body of the church was built in 1727-28); a museum for cork and the production of bottle corks in a defunct factory which is now also a centre for cultural events called “Fábrica do Inglês (The Englishman’s Factory); and the municipal museum (Museu Municipal de Arqueologia) with findings from the palaeolithic onwards.
The town is situated on a hill above the Arade River. Silves Castle (Castelo dos Mouros, Moorish Castle) is located on the top of the hill. It occupies ca. 12,000m². Archaeological excavations have shown that the oldest buildings date back to the 8th century, the stratigraphy is almost 6m deep and contains Iron Age remains as well. The walls are made of red sandstone (grés de Silves) with a pisé-core and have been heavily restored in the 1940s. Protruding towers of albarra-type protect the Northern slope. After the Christian conquest, the castle served as the seat of the alcaide-mor (provincial governor) till the middle of the 16th century, afterwards the towers were used as a prison.