The siege of Goa in 1570–1571 was a major military conflict between the Portuguese Empire and the Sultanate of Bijapur, as part of an alliance of Asian powers led by Ali Adil Shah I. This alliance aimed to expel the Portuguese from their strategic foothold in Goa, which was a crucial center for their colonial ambitions in Asia. The capital of Portuguese State of India was besieged by a large army commanded personally by Sultan Ali Adil Shah of Bijapur, in one of the greatest ordeals faced by the Portuguese in Asia, during which several of their strongholds were attacked simultaneously.

Viceroy Dom Luís de Ataíde organised the defence of Goa effectively and, after several months of spirited resistance by the Portuguese, the Sultan of Bijapur gave up the siege and signed a peace treaty favourable to Portugal. Dom Luís de Ataíde returned to Portugal in 1571 and was received in triumph at Lisbon by King Sebastian, who richly rewarded him and later reappoint him to the office of viceroy of India.

Context At the Battle of Talikota, the Deccan sultanates destroyed the power of the Vijayanagara Empire. Emboldened by their victory, the Nizam ul-Mulk of Ahmadnagar (Nizamaluco in Portuguese), and sultan of Bijapur (Hidalcão in Portuguese), formed an alliance aimed at recovering Chaul and Goa, which they had lost a few decades prior, but also at expelling the Portuguese from Asia.Saturnino Monteiro: Batalhas e Combates da Marinha Portuguesa, volume III, Livraria Sá da Costa Editora, 1992, p. 331.

As the sultans were well aware that whenever one Portuguese fortress was besieged all others would dispatch reinforcements by sea, as soon as they began gathering weapons and ammunition and mobilising their troops, they sought to convince as many rulers as possible to attack them at the same time. Thus, they dispatched ambassadors to the Zamorin of Calicut to convince him to attack the Portuguese fortress of Chaliyam; to the kings of the Malabar coast, urging them to attack the Portugueses fortresses at Honavar, Basrur and Mangalore, as well as to the Sultanate of Aceh, suggesting that he lay siege to Malacca once more. They also sent an embassy to the Ottoman Empire requesting that they contest the control of the sea from the Portuguese with their galley fleets.

The confidence of the sultans and the Zamorin in the plan led them to divide among themselves the territories that they intended to capture from the Portuguese. Thus, the Sultan of Bijapur would receive Goa, Honavar and Basrur, while the Nizam would receive Chaul, Daman and Bassein; the Zamorin would receive Cannannore, Mangalor, Cochim and Chalyiam. The Adil Shah went so far as to appoint his officers to positions at Goa in advance.Frederick Charles Danvers: The Portuguese in India, A. D. 1481-1571, W. H. Allen & Company Limited, 1894, p. 551.

Portuguese preparations

Reports and rumours about the machinations of sultans of Bijapur and Ahmadnagar reached Goa even before the end of the 1570 monsoon. Although skeptical at first, believing the distrust between Asian rulers to be insurmountable for such a plan to be possible, Viceroy Dom Luís de Ataíde eventually decided to dispatch a large armada of five galleons, one galley, two half-galleys, and five fustas, manned by 800 soldiers under the command of Luís de Melo da Silva to reinforce Malacca against a possible attack from the Sultanate of Aceh. Another fleet of three galleys and seventeen half-galleys with 500 men, under the command of Dom Diogo de Meneses was sent to patrol the Malabar coast and keep the vital trade routes with the Portuguese city of Cochin open and free of raiding from pirates. After such maneuvres, the viceroy was left with 1250 soldiers at Goa.

Once it became evident that the attacks on Goa and Chaul would indeed take place, the viceroy gathered a council with some of the highest figures in Goa, including noblemen, clergymen, and members of the city hall of Goa. Most favoured evacuating Chaul but as the viceroy considered that starting a war with a retreat was bad policy and that such a move wouldn't prevent the Nizam from then attacking Bassein, in October he sent four galleys and 600 soldiers under the command of captain-major Dom Francisco Mascarenhas to Chaul as reinforcements. Left with no more than 650 European soldiers at Goa, 1,500 Christian Goan auxiliaries, 1,000 slaves, 300 clerics, and 200 retired soldiers were mobilized and armed, thus increasing the garrison to 3,650 men, among professional soldiers and militiamen. The viceroy had four galleys, one half-galley and 20 fustas at Goa to defend the waters of the Mandovi and Zuari rivers around the island of Goa but as he had information that the Turks might join the "league", he armed a further vessels of various sizes to secure the control of the waters around Goa, although by then there weren't enough men to crew all the ships and defend the city simultaneously.

Conquered by Afonso de Albuquerque in 1510, Goa stood on an island surrounded by crocodile infested rivers that could be waded across in some areas during the dry season. The closest and most important fording point to the city of Goa was the Passo Seco ("Dry Pass"), defended by the fortress of Benastarim. Dom Luís distributed his forces in 19 critical points along the eastern river banks, where artillery batteries were established, garrisoned with 20 to 80 men and a contingent of lascarins, to keep the colossal army of Bijapur from crossing. Every battery was to have visual contact with the next and their garrisons were not to leave their posts unless ordered to.

Outside the island of Goa, the Portuguese also held the fortresses of Reis Magos, Naroá and Rachol, each garrisoned with 30 to 40 soldiers. The Fortress of Reis Magos was supported by an anchored galleon.

The siege

Ali Adil Shah of Bijapur disregarded the peace treaties he had once signed with the Portuguese and set out to attack Goa.Frederick Charles Danvers: The Portuguese in India, A. D. 1481-1571, W. H. Allen & Company Limited, 1894, p. 551.

By late December 1570, a large Bijapur army, commanded by general Nuri Khan, advanced towards Goa. Nuri Khan's vanguard arrived on December 28, 1570, followed by the main force under Ali Adil Shah I eight days later. The Bijapur forces established a camp east of the island of Goa, positioning their infantry ahead of Benastarim and deploying artillery to counter the Portuguese defenses.

By December 28, 1570, general Nuri Khan arrived with the vanguard of the Bijapur army, Ali Adil Shah himself arriving eight days later with the bulk of his forces. According to the Portuguese it numbered 100,000 men strong, of which 33,000 were infantry, including 3,000 arquebusiers, and 35,000 cavalry, plus 2,000 elephants, while the remaining were forced labourers. Besides over 350 bombards of which 30 were of colossal size, the army was also accompanied by several thousand dancing women. He established a camp around his red tent to the east of the island of Goa, the infantry distributed ahead of Benastarim and the artillery placed into position to counter-fire the Portuguese batteries. Its order of battle was:

4,000 horsemen, 600 musketeers, 300 elephants, and 220 cannons at Pondá, commanded personally by Ali Adil Shah;Danvers, 1894, p. 553. 3,000 horsemen, 130 elephants, and 9 cannon near the Ganja Canal, commanded by Cojer Khan, Rumi Khan, and Mortaz Khan; 7,000 horsemen, 180 elephants, and 8 large cannon in front of the Island of João Lopes commanded by Nuri Khan; 9,000 horsemen, 200 elephants, and 32 cannon in front of the Benastarim ford commanded by Camil Khan and Delirra Khan; 1,500 horsemen and 2 field guns in the hills opposite Benastarim commanded by Solimão Aga; 2,500 horsemen, 50 elephants, and 6 cannons opposite João Bangel Island commanded by Angozcan; 1,500 horsemen, 6 elephants and 6 cannons near Sapal commanded by Xatiarviatam; 9,000 horsemen, 200 elephants and 26 cannons in front of the Agaçaim ford commanded by Danlate Khan, Xatiatimanaique, Chiti Khan and Codemena Khan. The infantry ‘in vast numbers covered the hills and its purpose seemed to be to strike terror into the bravest spirits’.

Siege starts

Ali Adil Shah's forces began a relentless artillery bombardment on Portuguese fortifications, namely fort São Tiago of Benastarim but Portuguese continually repaired their defenses at night when the bombardment ceased.Danvers, 1894, p. 554. The forces of Bijapur however were unaware of the heavy casualties they inflicted upon the garrison within the fort. To deceive the Bijapur artillery and conserve their own resources, throughout the Portuguese lines by the river banks, the Viceroy ordered torches and bonfires be lit on isolated positions by night, to give the impression of readiness and encourage the enemy to waste ammunition firing on them. Portuguese ships patrolling the river waters under the command of Jorge de Meneses Baroche also fired at the forces of Bijapur stationed all along the river banks.

The siege coincided with the usual time at which Portuguese carracks would depart for Europe but although he was advised to hold them back to conserve their crews and personnel in the defense of Goa, Dom Luís instead authorized them to depart as normal, with accounts and reports to king Sebastian of the situation.

The soldiers and crews assigned to river patrol commanded by Jorge de Meneses Baroche rendered great service in the defence of Goa, unexpectedly attacking a little all along the enemy lines, bombarding the forces of Bijapur closest to the river banks and at times disembarking to assault their camps, successfully returning with captured banners, weapons and prisoners. The brothers Lançarote and Gaspar Dias torched two villages and several farms around Goa with a detachment of 80 soldiers and returned with captured cattle and prisoners, while on another occasion, they attacked the position of Cojer Khan and Rumi Khan and jeopardized the preparations they had made to attack the island of João Lopes.

Unable to ferry his troops across since the Portuguese controlled the river waters, the Adil Shah ordered that the Passo Seco along with the part of the river closest to the city be filled up with dirt to allow the army to cross over, forcing the labourers to dig under Portuguese fire:

By February 1571, the attack had ground down to a standstill, as the army of Bijapur was unable to overcome Portuguese defenses. Portuguese naval forces on the other hand, set to work devastating the shores and riversides of Bijapur, intercepting tradeships with provisions and capturing large quantities of livestock that was brought back to Goa. Because of its large population, foodstuffs had to be rationed to feed the troops, but the city suffered no starvation, as the Portuguese kept the naval supply routes open.

By the end of February, a large reinforcement of men and weapons arrived from Cochin.

In early March, Dom Luís de Melo returned from Malacca, having successfully defended that city from an Acehnese attack, and brought reinforcements from Cochin, totalizing 1500 men. On the 13th, the Adil Shah ordered a decisive assault across the river, under the command of a Turk, Suleimão Agá. 9,000 men waded across the river either by foot or on small crafts and many reached the opposite banks, but came under heavy fire from Portuguese ships, artillery batteries, and arquebuses, until they were finally shattered by a Portuguese counter-attack of 300 men under the command of Luís de Melo and Dom Fernando de Monroy, who landed on the opposite shore, killing about 3,000 enemies. By the late afternoon, a strong storm spelled the end of the assault.