Cão arrived in the Congo and he explored the extreme north-western coast of what today is Angola in 1484. Other expeditions followed, and close relations were soon established between the two states. The Portuguese brought firearms and many other technological advances, as well as a new religion (Christianity); in return, the King of the Congo offered plenty of slaves, ivory, and minerals. The Portuguese colony of Angola was founded in 1575 with the arrival of Paulo Dias de Novais with a hundred Portuguese families and four hundred soldiers. Its center at Luanda was granted the status of city in 1605. The King of the Kongo soon converted to Christianity and adopted a similar political structure to the Europeans. He became a well-known figure in Europe, to the point of receiving missives from the Pope. To the south of the Kingdom of the Kongo, around the river Kwanza, there were various important states. The most important of these was the Kingdom of Ndongo or Dongo, ruled by the ngolas. At the time of the arrival of the Portuguese, Ngola Kiluange was in power. By maintaining a policy of alliances with neighbouring states, he managed to hold out against the foreigners for several decades but was eventually beheaded in Luanda. Years later, the Ndongo rose to prominence again when Jinga Mbandi (Queen Jinga) took power. A wily politician, she kept the Portuguese in check with carefully prepared agreements. After undertaking various journeys she succeeded in 1635 in forming a grand coalition with the states of Matamba and Ndongo, Kongo, Kassanje, Dembos and Kissamas. At the head of this formidable alliance, she forced the Portuguese to retreat. Meanwhile, Portugal had lost its King and the Spanish took control of the Portuguese monarchy. By this time, Portugal's overseas territories had taken second place. The Dutch took advantage of this situation and occupied Luanda in 1641. Jinga entered into an alliance with the Dutch, thereby strengthening her coalition and confining the Portuguese to Massangano, which they fortified strongly, sallying forth on occasion to capture slaves in the Kuata! Kuata! Wars. Slaves from Angola were essential to the development of the Portuguese colony of Brazil, but the traffic had been interrupted by these events. Portugal having regained its independence, a large force from Brazil under the command of Salvador Correia de Sá retook Luanda in 1648, leading to the return of the Portuguese in large numbers.