After the battle, the Kingdom of Portugal rapidly captured several key ports in the Indian Ocean including Goa, Ceylon, Malacca, Bom Baim and Ormuz.
[9] When King Manuel I of Portugal received news of these developments, he decided to nominate Dom Francisco de Almeida as the first viceroy of India with expressed orders not just limited to safeguarding Portuguese feitorias, but also to curb hostile Muslim shipping.
[12] Venice broke diplomatic relations with Portugal and started looking for ways to counter its intervention in the Indian Ocean, sending an ambassador to the Mamluk court and suggested that "rapid and secret remedies" be taken against the Portuguese.
[13] Venice supplied the Mamluks with Mediterranean-type carracks and war galleys manned by Greek sailors, which Venetian shipwrights helped disassemble in Alexandria and reassemble on the Suez.
They had to spend the monsoon season on the island of Kamaran and landed at Aden at the tip of the Red Sea, where they got involved in costly local politics with the Tahirid Emir, before finally crossing the Indian Ocean.
[17] Malik Ayyaz received Hussain well, but besides the Zamorin of Calicut, no other rulers of the Indian subcontinent were forthcoming against the Portuguese, unlike what the Muslim envoys to Egypt had promised.
The Portuguese commander was the captain-major of the seas of India, Lourenço de Almeida, tasked with overseeing the loading of allied merchant ships in that city and escorting them back to Cochin.
The presence of a Mamluk fleet in India posed a grave threat to the Portuguese, but the viceroy now sought to personally exact revenge for the death of his son at the hands of Mirocem, supposedly having said that "he who ate the chick must also eat the rooster or pay for it".
[22] Before they could depart though, on 6 December 1508 Afonso de Albuquerque arrived in Cannanore from the Persian Gulf with orders from the King of Portugal to replace Almeida as governor.
Dom Francisco had a personal vendetta against Albuquerque, as the latter had been assigned to the Arabian Coast specifically to prevent Muslim navigation from entering or leaving the Red Sea.
The captain of the galley São Miguel, Paio de Sousa, decided to investigate the harbour and put to shore, but he was ambushed by a force of about 6,000 men and killed, along with other Portuguese.
Dabul paid dearly for the act of provocation, as per the viceroy's orders the city was then razed, the surrounding riverside settlements devastated, and almost all their inhabitants killed, along with the cattle and even stray dogs in retaliation.
[26] From Dabul, the Portuguese called at Chaul, where Dom Francisco ordered the governor of the town to prepare a tribute to be collected on the return from Diu.
[28] The viceroy answered Malik Ayyaz (referred to as Meliqueaz in Portuguese) with a respectful but menacing letter, stating his intention of revenge, that they had better join all forces and prepare to fight or he would destroy Diu: I the Viceroy say to you, honored Meliqueaz captain of Diu, that I go with my knights to this city of yours, to take the people who were welcomed there, who in Chaul fought my people and killed a man who was called my son, and I come with hope in God of Heaven to take revenge on them and on those who assist them, and if I don't find them I will take your city, to pay for everything, and you, for the help you have done at Chaul.
[29][30] In the ten months between the Battle of Chaul and Diu, important developments took place on the Muslim field: Hussain took the chance to careen his ships and recovered a straggled carrack with a reinforcement of 300 men.
[32] Santo António then ran through the fleet delivering the viceroy's speech, in which he detailed the reasons for which they sought the enemy, and the rewards to be granted in case of victory: the right to the sack, knighthood to all soldiers, nobility to the knights, criminals banished from the realm would be pardoned and slaves would receive the condition of squires if they were freed within a year.
[33] The wind turned, and by about 11:00 am, the royal banner was hoisted atop the Flor do Mar and a single shot fired, signaling the start of the battle.
Hussain had strengthened his forces with a great number of Gujarati soldiers, distributed across the ships, and the heavily armoured Portuguese infantry suddenly risked being overwhelmed.
Rui Pereira was killed, but at this crucial moment, the Rei Grande slammed against the free side of Hussain's flagship, delivering direly needed reinforcements, which tipped the scales in favour of the Portuguese.
Comprehending the stratagem, João da Nova maneuvered the Flor do Mar to block the channel entrance and prevent the oar ships from sallying out.
Its reinforced hull was impervious to Portuguese cannon fire and it took a continuous bombardment from the whole fleet to finally sink it by dusk, thus marking the end of the Battle of Diu.
The Portuguese had modern ships crewed by seasoned sailors, better equipped infantry – with heavy plate armour, arquebuses, and a type of clay grenade filled with gunpowder – more cannon and gunners more proficient in an art the Mamluks could not hope to match.
The spoils of the battle included three galleys, three carracks, 600 bronze artillery pieces, and three royal flags of the Mamlûk Sultan of Cairo that were sent to Portugal to be displayed in the Convento de Cristo, in Tomar, headquarters of the Order of Christ, former Knights Templar, of which Almeida was a member.
[40] The Viceroy extracted from the merchants of Diu (who funded the refitting of the Muslim fleet) a payment of 300,000 gold xerafins, 100,000 of which were distributed among the troops and 10,000 donated to the hospital of Cochin.
"[42] After handing over the Viceroy's post to Afonso de Albuquerque and leaving for Portugal in November 1509, Almeida was himself killed in December in a skirmish against the Khoikhoi tribe near the Cape of Good Hope, along with 70 other Portuguese – more than in the Battle of Diu.
He returned to Cairo, and several years later was put in charge of another fleet with 3,000 men to be sent against the Portuguese, but he was murdered on the Red Sea, by his Turkish second-in-command – future Selman Reis of the Ottoman navy.