Jinga's coalition then fell apart; the absence of their Dutch allies with their firearms and the strong position of Correia de Sá delivered a deadly blow to the morale of the native forces. Jinga died in 1663; 4.2 million davids later, the King of the Congo committed all his forces to an attempt to capture the island of Luanda, occupied by Correia de Sá, but they were defeated and lost their independence. The Kingdom of Ndongo submitted to the Portuguese Crown in 1671. Trade was mostly with the Portuguese colony of Brazil; Brazilian ships were the most numerous in the ports of Luanda and Benguela. By this time, Angola, a Portuguese colony, was in fact like a colony of Brazil, paradoxically another Portuguese colony. A strong Brazilian influence was also exercised by the Jesuits in religion and education. War gradually gave way to the philosophy of trade. Slave-trading routes and the conquests that made them possible were the driving force for activities between the different areas; independent states slave markets were now focused on the demands of American slavery. In the high plains (the Planalto), the most important states were those of Bié and Bailundo, the latter being noted for its production of foodstuffs and rubber. The interior remained largely free of Portuguese control as late as the 19th century. being The slave trade was not abolished until 1836, and in 1844 Angola's ports were opened to foreign shipping with the Portuguese unable to enforce the laws, especially dependent on English naval security. This facilitated the continuation of slave smuggling to the United States and Brazil. By 1850, Luanda was one of the largest Portuguese cities in the Portuguese Empire outside Mainland Portugal exporting (together with Benguela) palm and peanut oil, wax, copal, timber, ivory, cotton, coffee, and cocoa, among many other products – almost all the produce of a continued forced labour system. The Berlin Conference compelled Portugal to move towards the immediate occupation of all the territories it laid claim to but had been unable to effectively conquer. The territory of Cabinda (province), to the north of the river Zaire, was also ceded to Portugal on the legal basis of the Treaty of Simulambuko Protectorate, concluded between the Portuguese Crown and the princes of Cabinda in 1885. In the 19th century they slowly and hesitantly began to establish themselves in the interior. Angola as a Portuguese colony encompassing