Battle of Diu, 1509: the sea fight that gave Portugal the Indian Ocean

The Portuguese reached the Indian Ocean in 1498, and within a few years they were trying to channel the spice trade to Europe along their own route around the Cape of Good Hope. King Manuel ordered his captains to block Muslim shipping to the Red Sea and the Gulf. That set Portugal against the merchant networks of the Indian Ocean and the powers tied to them: the Mamluk sultan in Cairo, the Sultanate of Gujarat, the Zamorin of Calicut and, more distantly, the Ottomans.²

In 1505 Manuel sent Francisco de Almeida out as viceroy of India; Britannica gives his fleet as 21 ships. On the way he took Kilwa on the coast of East Africa and burned Mombasa, and in India he built forts at Cannanore and Cochin to hold the Portuguese position. The Muslim merchants of the coast asked the Mamluk sultan for help, and Cairo, with the support of Venice, fitted out a fleet against the Portuguese.³

Chaul and a father's revenge

In 1508 that fleet, under a commander the Portuguese called Mir-Hocem, the Emir Hussein, reached the coast of Gujarat. At Chaul it fought a Portuguese squadron and won. The Portuguese lost a ship and some 200 men, and among the dead was Lourenço de Almeida, the viceroy's son. The Mamluk fleet had won, but its losses left it unable to take the offensive, and it lay up in the harbor of Diu.⁴

Both accounts agree that two motives drove the viceroy. The Egyptian fleet had to be destroyed if the Portuguese were to stay in the Indian Ocean, and Almeida wanted to avenge his son. On 25 November 1508 he sailed from Cannanore with every ship he could gather.⁵

The fleets

The Portuguese arrived off Diu on 2 February 1509. The Navy Museum in Lisbon lists five large naus and four smaller ones, round and lateen-rigged caravels, galleys and a brigantine, carrying between 1,000 and 1,500 men, supported by about 400 Malabaris from Cochin. RTP Ensina counts 18 ships in all. The flagship was the great nau Flor de la Mar, and RTP Ensina notes that Ferdinand Magellan sailed with the fleet.⁶

The allied fleet was far larger in numbers but not in strength. The Navy Museum counts six large naus, six Turkish galleys and about 110 other craft, mostly fustas and paraus, the light oared boats of the coast. RTP Ensina gives nearly a hundred vessels, only twelve of them large ships. They lay in the harbor under the guns of the town's forts.⁷

The battle in the harbor

Almeida anchored at the mouth of the harbor, about a kilometer from the enemy. On the morning of 3 February, with the wind and the current behind them, the Portuguese ships moved in at a signal from the Flor de la Mar. They came under fire from the forts as they entered, and their plan was to close and board.⁸

The decisive blow, in the Navy Museum's account, fell to the nau Taforea Grande under Pêro Barreto, which put the Egyptian flagship and Mir-Hocem himself out of the fight. Only one Portuguese ship, the Santo Espírito, was hit, and it kept sailing and fighting. When the Flor de la Mar reached the inner harbor, it cruised through the scene of the battle so that the viceroy could watch the fighting and the victory.⁹

RTP Ensina puts the result down to heavier artillery and better-trained soldiers, which gave the Portuguese a marked superiority in their wars against the Muslim powers of the ocean. The Navy Museum lists four enemy naus sunk, six naus and two galleys captured and a large number of fustas and paraus sunk, for no Portuguese ship lost. By its count about thirty Portuguese were killed and some 300 wounded, against more than 3,000 dead on the Egyptian side.¹⁰

Malik Ayaz and the Gujarati side

Diu belonged to the Sultanate of Gujarat. According to the TDV Encyclopedia of Islam, the Gujarati governor of the region, Malik Ayaz, shared in the defeat and had to sign a treaty on the terms the Portuguese wanted. He remained a power on the coast, however: he fortified Diu, built a bridge to the mainland and for years kept the Portuguese out of the port they most wanted.¹¹

What Diu decided

The Navy Museum calls Diu a decisive battle in the strict sense, one in which a side loses all its naval power. It gave the Portuguese command of the Indian Ocean for about thirty years, until the Ottomans challenged them in 1538. RTP Ensina notes that some historians compare it to Lepanto. The victory carried Portuguese power to its height in the following years under Afonso de Albuquerque, while the loss of the fleet hastened the fall of the Mamluk sultanate, which the Ottomans conquered in 1517. That brought the Ottomans to the Red Sea, the next threat to the Portuguese.¹² › Battle of Lepanto, 1571

Almeida did not see that future. Replaced as governor by Albuquerque, he sailed for Portugal and was killed in a skirmish near the Cape of Good Hope in 1510. Britannica adds that he had at first refused to recognize his successor, giving way only in November 1509, and that he died fighting the Khoekhoe at Table Bay on 1 March.¹³