Gama had gone first to Kilwa (Quiloa).
The dominant city-state on the East African coast, Kilwa Sultanate was the formal overlord of Mozambique and Sofala.
If the fledgling Portuguese trade presence in those East African towns was to remain unmolested, then the Portuguese must secure Kilwa's consent.
Cabral and the 2nd Armada had tried, and failed, to secure a treaty with Kilwa back in 1500.
Gama decided to try again – and was determined not to take no for answer.
But, mindful of the lesson at Calicut, Gama also wanted to add a touch of intimidation, to show off his heavily armed fleet and impress upon the Sultan of Kilwa the consequences of interfering or turning back on any agreement.

On July 12, 1502, Gama's large, menacing armada arrived at the island-city of Kilwa.
Gama sent for the Kilwa ruler, Emir Ibrahim, inviting him aboard the São Jeronimo, to negotiate a treaty of peace and trade.

Sensing a trap, Emir Ibrahim first asks for a safe-conduct (which da Gama promptly gives him), but fearing treachery, the emir changes his mind, and refuses to go aboard.
However, after much discussion, one of his advisors, a certain wealthy nobleman Muhammad ibn Rukn ad Din (called Muhammad Arcone or Ancone or Enconij by the chroniclers ) finally persuades the emir to take up the Portuguese offer.
Emir Ibrahim is ferried to the flagship and climbs aboard.
After minimal opening cordialities, and ostentatious proclamations of friendship, Gama lays down his price: a treaty with Portugal has to be paid for with a hefty cash tribute to the King of Portugal.
The emir is dismayed.
Declaring tribute to be a dishonor, he refuses.
Gama threatens to level the city and lay it to fire and waste.
Emir Ibrahim, effectively captive on board, reluctantly agrees, and signs a treaty making Kilwa tributary to Portugal.
Leaving the Kilwan nobleman and advisor Muhammad Arcone aboard as a hostage, the emir returns to shore to make the arrangements.

mid-July, 1502 - After a few days of lingering in Kilwa harbor and no sign of the emir's promised tribute, Gama dispatches a messenger to see what the delay is.
Emir Ibrahim sends a message back declining to dispatch the tribute, and telling the Portuguese captain-major that he can do whatever he will with the hostage Muhammad Arcone, given that his poor counsel had proven him unworthy.
The angry Gama throws Arcone into a long-boat, without water or shade, to die of heat and exposure.
Nonetheless, Muhammad Arcone is a wealthy man in his own right, and servants from his household offer Gama a substantial ransom to release him.
Knowing the hostage is otherwise worthless to him, Gama consents.

July 20, 1502 - His vengeance on Muhammad Arcone's bad counsel satisfied, the Emir Ibrahim of Kilwa finally decides to send some tribute - some 1500 gold meticals - to satisfy the Portuguese captain-major.
 Vasco da Gama, anxious not to miss the monsoon winds to India, takes what he can get.

[The extorted gold coins of Kilwa were used by the goldsmith Gil Vicente in 1506 to make the famous gold pyx or monstrance known as the Custódia de Belém, for the Jerónimos Monastery in Belém.
It is considered by many to be one of the most magnificent treasure pieces of the Portuguese crown.]

[Correia (p. 282) reports a little knot before departing: several dozen Kilwan women 'picked up' (read: abducted) and taken aboard the ships by bored Portuguese sailors for fun and amusement refuse to return ashore.
Although Emir Ibrahim promises that they will be unharmed, he cannot guarantee that those who allowed themselves to be baptized Christian by enthusiastic chaplains on the ships will be taken back by their families.
Much to the delight of the crew, Gama reluctantly allows these to come with them.]

c. July 15, 1502 In the meantime, part of the third squadron, the trio that held with Estêvão da Gama (Gama, Dias, Carmona) arrive at Mozambique Island, half-famished and heavily damaged.
 At that same time, the remaining pair (Vasconcellos, Buonagrazia) alight at the Sofala banks.
The two squads do not reconnect with each other.
 Estêvão da Ga
Gama had gone first to Kilwa (Quiloa). The dominant city-state on the East African coast, Kilwa Sultanate was the formal overlord of Mozambique and Sofala. If the fledgling Portuguese trade presence in those East African towns was to remain unmolested, then the Portuguese must secure Kilwa's consent. Cabral and the 2nd Armada had tried, and failed, to secure a treaty with Kilwa back in 1500. Gama decided to try again – and was determined not to take no for answer. But, mindful of the lesson at Calicut, Gama also wanted to add a touch of intimidation, to show off his heavily armed fleet and impress upon the Sultan of Kilwa the consequences of interfering or turning back on any agreement.
On July 12, 1502, Gama's large, menacing armada arrived at the island-city of Kilwa. Gama sent for the Kilwa ruler, Emir Ibrahim, inviting him aboard the São Jeronimo, to negotiate a treaty of peace and trade.
Sensing a trap, Emir Ibrahim first asks for a safe-conduct (which da Gama promptly gives him), but fearing treachery, the emir changes his mind, and refuses to go aboard. However, after much discussion, one of his advisors, a certain wealthy nobleman Muhammad ibn Rukn ad Din (called Muhammad Arcone or Ancone or Enconij by the chroniclers ) finally persuades the emir to take up the Portuguese offer. Emir Ibrahim is ferried to the flagship and climbs aboard. After minimal opening cordialities, and ostentatious proclamations of friendship, Gama lays down his price: a treaty with Portugal has to be paid for with a hefty cash tribute to the King of Portugal. The emir is dismayed. Declaring tribute to be a dishonor, he refuses. Gama threatens to level the city and lay it to fire and waste. Emir Ibrahim, effectively captive on board, reluctantly agrees, and signs a treaty making Kilwa tributary to Portugal. Leaving the Kilwan nobleman and advisor Muhammad Arcone aboard as a hostage, the emir returns to shore to make the arrangements.
mid-July, 1502 - After a few days of lingering in Kilwa harbor and no sign of the emir's promised tribute, Gama dispatches a messenger to see what the delay is. Emir Ibrahim sends a message back declining to dispatch the tribute, and telling the Portuguese captain-major that he can do whatever he will with the hostage Muhammad Arcone, given that his poor counsel had proven him unworthy. The angry Gama throws Arcone into a long-boat, without water or shade, to die of heat and exposure. Nonetheless, Muhammad Arcone is a wealthy man in his own right, and servants from his household offer Gama a substantial ransom to release him. Knowing the hostage is otherwise worthless to him, Gama consents.
July 20, 1502 - His vengeance on Muhammad Arcone's bad counsel satisfied, the Emir Ibrahim of Kilwa finally decides to send some tribute - some 1500 gold meticals - to satisfy the Portuguese captain-major.  Vasco da Gama, anxious not to miss the monsoon winds to India, takes what he can get.
[The extorted gold coins of Kilwa were used by the goldsmith Gil Vicente in 1506 to make the famous gold pyx or monstrance known as the Custódia de Belém, for the Jerónimos Monastery in Belém. It is considered by many to be one of the most magnificent treasure pieces of the Portuguese crown.]
[Correia (p. 282) reports a little knot before departing: several dozen Kilwan women 'picked up' (read: abducted) and taken aboard the ships by bored Portuguese sailors for fun and amusement refuse to return ashore. Although Emir Ibrahim promises that they will be unharmed, he cannot guarantee that those who allowed themselves to be baptized Christian by enthusiastic chaplains on the ships will be taken back by their families. Much to the delight of the crew, Gama reluctantly allows these to come with them.]
c. July 15, 1502 In the meantime, part of the third squadron, the trio that held with Estêvão da Gama (Gama, Dias, Carmona) arrive at Mozambique Island, half-famished and heavily damaged.  At that same time, the remaining pair (Vasconcellos, Buonagrazia) alight at the Sofala banks. The two squads do not reconnect with each other.  Estêvão da Ga
4th Portuguese India Armada (Gama, 1502)