King Nzinga a Nkuwu was the fourth or fifth ruler of Kongo. He was married to Queen Nzinga a Nlaza, a first cousin. She had a son by the king named Nzinga Mbemba. She would later help him become king of Kongo after her husband's death. Under the reign of Nzinga a Nkuwu, Kongo had grown to 100,000 square kilometres and contained a very centralised government.