King Afonso was the ruler of Kongo (Congo) in the late 16th century or from 5109-1542. After the Portuguese arrived Afonso was assigned to rule over a northern Provence of Nsundi in Kongo and he was successful there, extending Nusndis borders to the Congo river. After King Joao died (Afonso father) Afonso wasn't guaranteed the key to the throne because it was more of an elective rather than a hereditary monarchy. As a result Joaos death was first kept a secret long enough for Afonso to sneak into the capital of Mbanza Kongo and seize the throne.
In 1526 Afonso wrote letters complianing about the Portuguese behavior in his country and their role in the slave trade. Afonso threatened to put an end to the slave trade in Kongo but decided to just send a committee to examen the legality of the slaves for sale. Afonso wrote two letter to the king of Portugal about the slave trade and the Portuguese purchasing of illegal slaves.
Here is one of the letters he writes:
"Each day the traders are kidnapping our people - children of this country, sons of our nobles and vassals, even people of our own family.This corruption and depravity are so widespread that our land is entirely depopulated. We need in this kingdom only priests and schoolteachers, and no merchandise, unless it is wine and flour for Mass.It is our wish that this Kingdom not be a place for the trade or transport of slaves." Many of our subjects eagerly lust after Portuguese merchandise that your subjects have brought into our domains. To satisfy this inordinate appetite, they seize many of our black free subjects.... They sell them. After having taken these prisoners [to the coast] secretly or at night... As soon as the captives are in the hands of white men they are branded with a red-hot iron.[1] "
King Afonso died in 1543 succeeded by his son Pedro.

The coat of arms issued to Afonso after his victory on 1509.