By 1513, D. Pedro and King Manuel I of Portugal had known each other for a long time.  Around the time that this letter was written, D. Pedro was returning to Africa from Portugal and had recently been in Rome. Less than a year passed between his assignment as bishop and his reference to himself as “ambassador of the King of the Congo.” When D. Pedro felt he was being discriminated against by corrupt merchants in São Tomé, he did not hesitate to bring his grievance directly to Manuel I.

Luis Serrão, named in the text as a factor for the island of São Tomé, did not leave much of a documentary trail. We do, however, have a scathing letter sent to Manuel I in 1509 from Pedro Ferreira of São Jorge da Mina charging the officials of São Tomé with stealing trade goods and colluding with officials in the Casa da Mina.[1]

Some context is necessary to understand D. Pedro’s complaint. In a 1485 decree, the residents of São Tomé were relieved from paying customs taxes.[2] So, if a shipment of slaves passed through customs in São Tomé on the way to Portugal, no taxes were paid to Portugal. In 1493 they were awarded another license to collect taxes when delivering items to any West African trading house.[3]  There was a significant amount of reciprocal trade within West Africa, most of which passed through São Tomé. So, if a shipment of slaves from the Congo passed through São Tomé on the way to the Casa da Mina, the factor in São Jorge da Mina paid a service tax to the tax collector in São Tomé who expedited and facilitated this trade. For one slave the service tax was four thousand reais.[4]

To give an idea of the kind of revenue that these taxes generated we can look at an order from D. Manuel to the tax collector, Gonçalo Lopez, in 1515. Bartolomeu Dias should receive 78,000 reais in order to pay one thousand reais per slave from Manicongo who were lost in shipwreck.[5] The receipt shows that Lopes gave Dias 38,000 reais as down payment and, later, 40,000 reais for 38 slaves,[6] suggesting that the 38,000 was for replacing the lost slaves and the 40,000 was compensation for the loss. If those slaves were then shipped to the Casa da Mina, the service tax would yield 25% of their value.

In the text translated below, we see that D. Pedro was familiar with the commodity slave market as he used terminology specific to it and demonstrated familiarity with the tax laws. D. Pedro protests being charged customs taxes, and perhaps service taxes, on slaves he had brought to São Tomé. As bishop of São Tomé, he was likely considered a resident by law and should not be subject to customs taxes as decreed in 1485. Since some of the slaves he brought were destined for Portugal, he should certainly not have been required to pay the service tax for intra-African trade as decreed in 1493. When D. Pedro speaks of “your naturals” (seus naturães), he is likely referring to Portuguese citizens from the Casa da Mina who may not have qualified for the exemptions that the residents of São Tomé did.


[1] Konadu, Africa’s Gold Coast, 67.

[2] Brásio, Monumenta Missionaria, 50.

[3] Konadu, Africa’s Gold Coast, 10.

[4] Konadu, Africa’s Gold Coast, 11.

[5] Brásio, Monumenta Missionaria, 339.

[6] Brásio, Monumenta Missionaria, 340.

Don Pedro de Sousa, ambassador of the King of Congo. I make known to Your Highness that coming with the embassy of the King my Lord, I arrived at the island of São Tomé and there I encountered Luis Serrão, factor of its merchants. Of certain pieces of slaves,[1] whom I brought for my use and from my people, he took as customs tax[2] eight and a half pieces of slaves from me. And why, Lord, does the King my Lord exempt all the merchandise in his kingdom that the white men there [in São Tomé] and those same merchants bring. Your naturals don’t do anything other than pay all their duties according to the ordinance. It seems to me, my Lord, it would be without reason [to charge them taxes], however, if they don’t take any of them there [to the Casa da Mina]. I will carry out as the King commands, taxes, because seven of those pieces were for the King and one and a half were mine.[3] I pray Your Highness to  order Luis Serrão, or the merchants, his friends,[4] that they return my pieces to me, that they don’t receive mercy.


[1] Peças descravos. The unit peça da Índia was 1.75m, the standardized height of a Black man. J. Lúcio de Azeveda, Épocas de Portugal económico (Lisbon: Livraria clássica editora de A.M. Teixeira & Ca., 1929), 77-78.

[2] Translating direitos as taxes. In a letter from King Affonso of Manicongo to King João of Portugal in 1517, King Affonso requests permission to buy a ship, and in the event that his request is denied he asks tax exemption on parts of his slave shipments (certas peças sem delas pagar direitos). Brásio, Monumenta missionaria, 404. See “Direito,” Dicionário da Língua Portuguesa (Academia das Ciências de Lisboa). Accessed April 20, 2024. https://dicionario.acad-ciencias.pt/pesquisa/?word=direito#w1 )

[3] We don’t know how many “certain pieces of slaves” (certas peças descravos) means, but the passage points to the notion that the eight and a half slaves were exacted from a larger pool.

[4] Seus amos could mean “his friends” or “his masters.” Masters would represent sarcasm on the part of D. Pedro, since a factor should have authority over a merchant in spite of the fact that the merchant often made more money.

Discussion Questions

  1. What can we learn from this source about the internal workings of the early Portuguese trade in slaves from various parts of West Africa?
  2. Why do you think the Portuguese officials in São Tomé tried to collect taxes on D. Pedro’s slaves? What assumptions must they have made about D. Pedro in order for their actions to make sense?
  3. D. Pedro mentions that, of the 8.5 “pieces of slaves” collected as taxes, 7 were for the king and 1.5 were for himself. What can we learn from this about Portuguese royal involvement in the early West African slave trade?

Related Primary Sources