From the 1570s, the European traders arrived in large numbers and the slave trading through the Kongo people territory dramatically increased. The weakened Kingdom of Kongo continued to face internal revolts and violence that resulted from the raids and capture of slaves, and the Portuguese in 1575 established the port city of Luanda (now in Angola) in cooperation with a Kongo noble family to facilitate their military presence, African operations and the slave trade thereof. The Kingdom of Kongo and its people ended their cooperation in the 1660s. In 1665, the Portuguese army invaded the Kingdom, killed the Kongo king, disbanded his army, and installed a friendly replacement in his place.