Ilha de Palma, the island of Palms. The Portuguese did not settle there permanently, but used the site for landing and engaged in commerce in the region. They built a chapel there in 1481. Portuguese trading posts were installed in Tanguegueth in Cay, a town they renamed Fresco Rio (the future Rufisque) because of the freshness of its sources in the Baol Sali (later the seaside town of Saly) which takes the name of Portudal, or to Joal in the Kingdom of Sine. They also traversed the lower Casamance and founded Ziguinchor in 1645. The introduction of Christianity accompanied this business expansion. The Dutch West India Company After the Act of Abjuration in 1581, the United Provinces flouted the authority of the King of Spain. They based their growth on maritime trade and expanded their colonial empire in Asia, the Americas and South Africa. In West Africa trading posts were opened at some points of the current Senegal, Gambia, Ghana and Angola. Created in 1621, the Dutch West India Company purchased the island of Gorée in 1627. The company built two forts that are in ruins today: in 1628 on the face of Nassau Cove and 1639 at Nassau on the hill, as well as warehouses for goods destined for the mainland trading posts . In his Description of Africa (1668), the humanist Dutch Olfert Dapper gives the etymology of the name given to it by his countrymen, Goe-ree Goede Reede, that is to say "good harbor"., which is the name of (part of) an island in the Dutch province of Zeeland as well. The Dutch settlers occupied the island for nearly half a century, dealing in wax, amber, gold, ivory and also participated in the slave trade, but kept away from foreign trading posts on the coast. The Dutch were dislodged several times: in 1629 by the Portuguese, in 1645 and 1659 by the French and in 1663 by the English. Against the backdrop of Anglo-French rivalry The "trade" and the slave trade intensified in the 17th century. In Senegal, the French and British competed mainly on two issues, the island of Gorée and St. Louis. On 10 February 1763 the Treaty of Paris ended the Seven Years' War and reconciled, after three years of negotiations, France, Great Britain and Spain. Great Britain returned the island of Gorée to France. Britain then acquired from France, among many other territories,