The siege of Chaul was a military operation undertaken by the Ahmadnagar Sultanate against the Portuguese city of Chaul in the Maharashtra, India, between December 1570 and July 1571. Chaul was not walled at the time, but after a harsh seven-month siege the Portuguese repelled the attackers in what was one of the hardest ordeals they faced India.

Portuguese success in this siege drew the attention of 20th-century scholars owing to the tactics employed.R. O. W. Goertz: "Attack and Defense Techniques in the Siege of Chaul, 1570-1571." in II Seminário Internacional de História Indo-Portuguesa - Actas, Instituto de Investigação Científica e Tropical, Lisboa 1985, pp. 267-287.

Background The Sultanate of Ahmadnagar was an Indian state located on the Deccan Plateau that had authorised the Portuguese governor of India Diogo Lopes de Sequeira to found a fortress and city at Chaul. Thus, the Portuguese secured at Chaul a supply of raw cotton, the manufacture of cotton fabrics and their export.Luís Frederico Antunes: "Chaul | Enciclopédia Virtual da Expansão" in eve.fcsh.unl.pt/pt The Nizam ul-Mulk of Ahmadnagar, known as Nizamaluco among the Portuguese, had maintained good relations with the Portuguese State of India and paid Portugal a tribute of 7,000 pardaus in exchange for help fighting piracy, but in the mid-16th century he joined an alliance of Islamic sultanates which, at the Battle of Talikota, inflicted a heavy defeat on the great Hindu Vijayanagara Empire, itself a major partner of the Portuguese. After the death of Rama Raya, Nizamaluco and his allies turned on the Portuguese. The Sultan of Bijapur, known as Hidalcão attacked Goa, and Nizamaluco attacked Chaul, disregarding all the trade and friendship treaties he had signed with the Portuguese until then.

Around 2,000 Portuguese lived in Chaul, trading with Mozambique, the Persian Gulf, China and Manila. In addition, hundreds of dhows anchored in Chaul every year between December and March, mainly from the Malabar Coast but also from the Middle East and Gujarat. In addition to the buildings necessary for the administration, justice and defence of the port, the city had a hospital, a Misericórdia (charity), several churches and five monasteries, belonging to the Franciscans, Dominicans, Augustinians, Jesuits and Capuchins. Its most important and influential inhabitants also had stately homes.

Portuguese preparations Although protected by a small fort built near the shoreline in 1521, the city of Chaul was not fortified. The Portuguese were prevented by a 1558 treaty from walling the city.Goertz, 1985, p. 270. The garrison of Chaul numbered 50 horsemen and about 250 foot soldiers. Just as the threat of a siege became evident, the captain of the city, Dom Luís Freire de Andrade ordered the evacuation of women, children, and elderly to Goa and barricades be set up in the main streets with artillery.

The residents of Chaul initially resisted the digging of trenches, the barricading of streets, the demolition of houses and the building of defence works, and wood, stones and earth had to be brought in from far away, but as the threat of a siege became evident, they began to participate more actively, but also to insisting that the captain not leave their houses out of the fortification works. In October, a fleet arrived from Goa with 600 soldiers in reinforcements, commanded by Captain-majoe Dom Francisco de Mascarenhas, who immediately ordered the opening of an extensive network of moats, trenches, earthen walls, and defensive works around the entire outer perimeter of the city, fortifying outer houses and monasteries into blockhouses or redoubts and demolishing others to clear the line of fire for the artillery.Pereira 1617, p. 361-353. Bastions were built every 200 metres, artillery batteries were installed every 50 metres, and the last line of defence formed a triangle.

The warships were distributed in the river to the east, so as to deny the enemy a venue of approach to the city along the river banks with their artillery.Goertz 1985, p. 274. This way, it would only be possible to approach the city through a narrow, marshy section to the north, forcing the enemy to bottleneck their forces.Goertz 1985, p. 282.

Battle The Ahmadnagar army also faced its own challenges in attacking Chaul. New roads had to be carved out of the Western Ghats mountain range in order to transport artillery across it. Ahmadnagar had signed peace and trade treaties with Portugal which were still standing at the time of the siege, but these were disregarded and he departed to Chaul with his forces.

On December 15, the vanguard of the army of Ahmadnagar arrived under the command of an Ethiopian general, Faratecão (formerly at the service of the Sultan of Gujarat), and clashed with the Portuguese, who repelled the attack. The Nizam arrived with the rest of his army on December 21. Through a spy, the Portuguese determined that the forces of the Nizam Ul-Mulk Shah of Ahmadnagar (Nizamaluco in Portuguese) might have risen up to 120,000 men, including many Turkic, Abyssian, Persian, Afghan, and Mughal mercenaries, 38,000 horsemen, and 370 war elephants, supported by 38 heavy bombards. Not all were fighting men; according to António Pinto Pereira:The infantry passed one-hundred and twenty thousand, but they do not rest on them their strength, nor do they care but of the cavalry and artillery for matters of war; the footmen are brought along for the march and for service in the camp and as labourers, rather than any confidence they might have of them. In said camp came 12,000 konkanis, very good people in war, mustered by the tanadares of Konkan, which lays between the edge of the Ghats and the sea, as bomb throwers, bowmen and a few arquebusiers and 4,000 field craftsmen, blacksmiths, stonemasons and carpenters.

The Nizams artillery out-ranged that of the Portuguese. He brought to bear 11 large cannon that fired 45 to 80, 100, 200 and even 300 pound cannonballs. The other 27 pieces were 36, 24 and 16-pounders. The Portuguese on the other hand had at best 12-pounder cannon that weighted 4000 pounds and required 20 horses to position or 8-pounders weighting 2400 pounds that required 12 horses to position, but lacking the horses the Portuguese would have to position them by hand. Other cannon were 2 and 4-pounders weighting 600 to 1800 pounds.

The great advantage of the Portuguese lied in their infantry, only 900 soldiers strong but each equipped with steel-plate armour, arquebuses and muskets capable of firing a 50 gram bullet as far as 400 meters, compared to only 300 arquebusiers on the enemy side, with less powerful and accurate weapons.Goertz 1985, p. 276. The defenders on the Portuguese side numbered 1100 or 1200 men total among soldiers, auxiliaries, and civilian militia.Goertz 1985, p. 277. Once the dire situation at Chaul became known however, numerous Portuguese volunteered to sail in the aid of the beleaguered city, so that soon there were as many as 2000 soldiers.Danvers, Frederick Charles (1894). The Portuguese in India A.D. 1481-1571, W. H. Allen Company Limited, p. 561.

The Nizam assembled the rest of his forces around the north and northeast of the city. As his cavalry and elephants were useless in a siege, his infantry would have to bear the brunt of the assault.Goertz 1985, p. 282.

On the 21st day of December he breached the fortified perimeter around the monastery of São Francisco on the outskirts of Chaul, but the heavy fire of the Portuguese arquebuses and a swift counter-attack forced them to retreat. In the meantime, the Nizam set his powerful artillery to the east of the city under the supervision of a Turkish general, Rumi Khan, near a village the Portuguese dubbed Chaul de Cima (Upper Chaul).

Meanwhile, about 2,000 horsemen proceeded to devastate the lands owned by Portuguese around Bassein and Daman, but were repelled trying to assault a small Portuguese fort at Caranjá near Bombay, defended by 40 Portuguese soldiers.

Bombardment begins

On January 10, the batteries of the Nizam began bombarding the outer blockhouses of Chaul, reducing them to rubble after a few days. One such piece earned from the Portuguese the nickname "Orlando Furioso". Buried under the stones and beams of houses turned to redoubts and fortlets but which collapsed under the weight of the bombardment, the Portuguese would at the same time carry out sallies and coups-de-main against enemy lines. They suffered considerable casualties due to the enemy bombardment, while the besiegers lost many men due to the constant skirmishes with the Portuguese, who usually held the upper-hand in hand-to-hand combat.

Fighting around Chaul broke down to trench warfare, as the army of Ahmadnagar dug trenches towards Portuguese lines to cover from their gunfire, amidst frequent Portuguese raids, only tens of meters apart from each other. The Portuguese dug counter-mines to neutralize them. Day after day the fighting became more brutal as the Portuguese gradually abandoned their outer blockhouses and defenses, pressured by the enemys numerical superiority.Monteiro, 1992, p. 338.

At this point, a Portuguese captain Agostinho Nunes introduced for the first time an innovation that the Portuguese historian António Pinto Pereira considered to have been critical in withstanding the enemy bombardment: he ordered his soldiers to dig a special trench with a firing parapet, protected by sloped earth—a "fire trench". This invention was later mis-attributed to the Dutch.

On Friday January 19 the Muslim zigzag trenches reached the monastery of São Francisco. An assault took place the following day, but the Portuguese repelled it. A three-day bombardment following during which the Portuguese prepared their retreat along a coastal wall leading back to the monastery of São Domingos, taking their guns with them and set fire to the stronghold. In the last week of January the enemy was able to position their guns on São Francisco and begin bombarding Portuguese positions as far as São Domingos.Goertz, 1985, pp. 278-280.

In February, a small fleet of 5 half-galleys and 25 smaller craft with 2,000 men from Calicut, commanded by Catiproca Marcá, arrived in Chaul to meet up with the forces of the Nizam, under cover from the night. The Portuguese had five galleys and eleven foists in the harbour, but the Malabarese avoided clashing with the Portuguese galleys.

In late February the Nizam ordered a general assault on the city, but was repelled with heavy losses, just as the Portuguese received important reinforcements by sea from Goa and Bassein. The Nizam observed all the actions of his army closely, and the Portuguese could see him reprimanding his men for their cowardlyness and threatening them with a whip.Danvers, 1894, p. 566. Fighting continued over the possession of the outer strongholds throughout the months of March and April, as the army of the Nizam suffered heavy casualties. Following a sortie of the Portuguese on April 11, the Nizam ordered the city to be subjected to a general bombardment, which demolished several strongholds and sunk the Viceroy's galley anchored in the harbour.