The first written accounts of the region come from records of Arab traders in the ninth and tenth centuries AD. In 1066, the inhabitants of Tekrur, a kingdom centered on the Sénégal River just to the north, became the first people in the region to convert to Islam. Muslim traders established the trans-Saharan trade route for slaves, gold, and ivory. At the beginning of the fourteenth century, most of what is today called The Gambia was a tributary to the Mali Empire. The Portuguese reached the area by sea in the mid-fifteenth century and began to dominate the lucrative trade.
In 1588, the claimant to the Portuguese throne, António, Prior of Crato, sold exclusive trade rights on the Gambia River to English merchants; this grant was confirmed by letters patent from Queen Elizabeth I. In 1618, James I granted a charter to a British company for trade with Gambia and the Gold Coast (now Ghana). Between 1651-1661 some parts of Gambia was under Courland's rule, bought by prince Jacob Kettler, who was Polish vassal.
During the late seventeenth century and throughout the eighteenth, Britain and France struggled continually for political and commercial supremacy in the regions of the Senegal and Gambia rivers. The 1783 Treaty of Versailles gave Great Britain possession of the Gambia river, but the French retained a tiny enclave at Albreda on its north bank, which was ceded to the United Kingdom in 1857.