
Historians speak of her as "a legend in her lifetime, who, with her heroics, was able to preserve the sovereignty of the peoples of Angolaand because of this she became a symbol in the whole Congo basin."
Njinga first appears in the historical records as the envoy of her brother, the King Ngola Mbande at a peace conference with the Portuguese governor João Correia de Sousa in Luanda in 1622.
The immediate cause of her embassy was her brother's attempt to get the Portuguese to withdraw the fortress of Ambaca that had been built on his land in 1618 by the Governor Mendes de Vasconcelos, to have some of his subjects who had been taken captive during Governor Mendes de Vasconcelos' campaigns (1617–21) returned and to persuade the governor to stop the marauding of Angolan mercenaries in Portuguese service. Queen Njinga's efforts were successful. The governor, João Correia de Sousa, never gained the advantage at the meeting and agreed to her terms, which resulted in a treaty on equal terms. One important point of disagreement was the question of whether the Ndongo Kingdom surrendered to Portugal and accepted vassalage status.
A famous story says that in her meeting with the Portuguese governor, João Correia de Sousa did not offer a chair to sit on during the negotiations, and, instead, had placed a floor mat for her to sit, which in Mbundu custom was appropriate only for subordinates. The scene was imaginatively reconstructed by the Italian priest Cavazzi and printed as an engraving in his book of 1687. Not willing to accept this degradation she ordered one of her servants to get down on the ground and sat on the servant's back during negotiations. By doing this, she asserted her status was equal to the governor, proving her worth as a brave and confident individual.
Njinga converted to Christianity, possibly in order to strengthen the peace treaty with the Portuguese, and adopted the name Dona Anna de Sousa in honour of the governor's wife when she was baptised, who was also her godmother. She sometimes used this name in her correspondence (or just Anna). The Portuguese never honoured the treaty however, neither withdrawing Ambaca, nor returning the subjects, who they held were slaves captured in war, and they were unable to restrain the mercenaries.
In 1657, weary from the long struggle, Njinga signed another peace treaty with Portugal. After the wars with Portugal ended, she attempted to rebuild her nation, which had been seriously damaged by years of conflict and over-farming. She permitted Capuchin missionaries, first Antonio da Gaeta and the Giovanni Antonio Cavazzi da Montecuccolo to preach to her people. Both wrote lengthy accounts of her life, kingdom, and strong will.

Today, she is remembered in Angola for her political and diplomatic acumen, great wit and intelligence, as well as her brilliant military tactics. In time, Portugal and most of Europe would come to respect her. A major street in Luanda is named after her, and a statue of her was placed in Kinaxixi on an impressive square. Angolan women are often married near the statue, especially on Thursdays and Fridays. (TAAG Austral Magazine, Wikipedia)