Silves is located in the Barlavento ( the western part ) of the Algarve, between the mountains and the coast, an intermediate stripe known as Barrocal. Its geographic coordinates are latitude 37° 11' 13'' N and longitude 8° 26' 20'' W from the Greenwich meridian. The townscape suggests an amphitheatre form in the hill, whose height is 55m above the river Arade which flows into the sea in Portimão.

This area has been inhabited since prehistoric times and archeological findings are most frequently discovered in the Arade basin and in its margins: menhirs, tombs, polished stone tools. However, it would be in the Ages of Metal, from the third millenium B. C. on, due to its richness in copper, that the region will gradually become more important. The Arade river then became an important entrance to eastern mediterranean commerce and cultural interchanges. During the first millenium B. C. written documents increased in number, although their particular code, which had its origins in the Peninsular Southwest, had not yet been deciphered. The presence of Greeks, Phoenicians and Carthageneans who came to trade was also felt. By that time the first urban settlement was probably known as Cilpes and its probable localization was on the Cerro da Guerrilha, 1Km west of the actual Silves.

The Roman dominion was strengthened after the defeat of the Carthageneans in the Punic Wars. The Arade river continued to be the main sea entrance of foreign influences and the outlet of the local products as ores, oil, wine, dried fruits, salt and fish. Roman vestiges are not frequently found near Silves: only small statuettes, pedestals, engraved stones, coins, remains of "Villas". We do not consider accurate the tradition that says that the bridge is Roman. The Roman dominion lasted politically until the 5th century as well as its cultural influence, even under the Visigothic reign, which ended under the Arabic conquest in the 8th century.

The Islamic culture brought a wind of civilization to al-Andaluz and in particular to the rural al-Gharb ( origin of the word Algarve ) inherited from the Roman empire. The Muslim town was an economical, cultural and administrative center of a contiguous area or alfoz. Silves was at that time an important city sung by its poets not only during the Emirat but also under the Caliphate of Cordova or in its role of regional capital of Taifa kingdoms. Al-Mu'tamid made it a center of refuge of many poets, scientists, theologians who were received in his palace, schools and litterary gatherings. In the following century, Ibn Qasi who called himself the Messiah ( Madhi ), led an anti-Almorávida religious revolution in the Gharb.

The first step forward in Portuguese expansion was the assault on the Moor port of Ceuta in 1415. King João I (John I) and his sons had organised this expedition to conquer Ceuta that lay across the Straits of Gibraltar on the coast of North Africa. It was an expensive enterprise that failed to recover the cost of the expedition or the three thousand men left by Prince Pedro to garrison the town. Although a financial failure, the fall of Ceuta greatly added to the prestige of King João I, his sons and to Portugal. This experience in North Africa would stimulate the minds of the Princes Pedro and Henry, each would become a life-long supporter of overseas expansion.

During this period there had been a shortage of gold that increasingly hindered the growth of European trade. Ceuta had been a part of a centuries-old traffic in the products of the trans-Saharan caravan routes that provided a source of gold rumoured to have originated in a wealthy nation that lay across the Sahara Desert known as Guinea. The possibility of gold in this new land was too tempting for the Portuguese to resist. They pursued the idea of discovering a sea route to Guinea that would allow them to by-pass the caravan route that was controlled by their enemies the Moors.