The 33-month siege of Fort Jesus, Mombasa, 1696 to 1698

On 11 March 1696 seven ships from Muscat appeared off the bar of Mombasa. According to the Portuguese chronicle of the siege, they carried 3,000 men and the Prince of Lamu, a Swahili ruler allied to Oman. The wind was against them, and for two days they could not get in.1 source1 source

On the 13th they tried the channel. The flagship ran onto a sandbank at its entrance, and as she grounded her bow came to rest facing the small fort that guarded the passage. A couple of shots from her bow guns were enough. Its garrison, 300 Swahili and four Portuguese, ran without firing back.1 source1 source

After some hours the Omanis refloated the ship, then took the town and island unopposed. For eight days they did nothing more. On a coral ridge above the harbour stood Fort Jesus, with about fifty Portuguese soldiers inside, and its governor used the pause to fill it with food, arms and people.2 sources2 sources

The siege that began that day ran for 33 months, until 13 December 1698. The historian C. R. Boxer called it one of the most remarkable sieges in history, for its length, for the loyalty of the Muslim defenders to a Christian king they had never seen, and for the lack of initiative shown by the commanders on both sides.2 sources2 sources

Mombasa was one of the trading towns of the Swahili coast, the Muslim, Swahili-speaking ports that ran from Somalia to Mozambique and lived on the Indian Ocean trade in ivory, gold and slaves. Relations with the Portuguese went wrong from Vasco da Gama's first visit. Portuguese fleets sacked the town in 1505 and again in 1529, while its rival Malindi became Portugal's firm ally.1 source1 source

For most of the sixteenth century Portugal held the coast by sea alone, with a “captain-major of the Sea of Malindi” and a few small ships. That changed when an Ottoman captain, Mir Ali Bey, raided down the coast with a handful of ships in 1585 and 1586 and again in 1588 and 1589, and most of the Swahili towns submitted to him. On 21 January 1591 the Crown, then held by Philip II of Spain, authorised a fortress at Mombasa.1 source1 source

The plan came from Giovanni Battista Cairati, or João Batista Cairato to the Portuguese, the Italian chief architect of Portuguese India. Work began on 11 April 1593 under Mateus Mendes de Vasconcelos, with the Sultan of Malindi's men helping to carry the coral stone. The fort was nearly square, with four corner bastions, a design that followed Renaissance theories of proportion.2 sources2 sources

The fort did not keep the town loyal. In August 1631 Mombasa's own sultan, Yusuf bin Hasan, raised a Christian in Goa as Dom Jerónimo Chingulia, entered Fort Jesus during a feast day and killed the garrison. Portugal got the fort back only after he abandoned it in 1632.1 source1 source

The threat in 1696 came from Arabia. After the Portuguese lost Hormuz in 1622, their power in the Persian Gulf rested on Muscat, in Oman. In 1650 Oman's Ya‘rubi dynasty of imams drove them out of Muscat as well.2 sources2 sources

Oman had sailors but no warships able to stand up to Portuguese guns. In 1650 and 1651 it captured several Portuguese vessels, and Boxer argues that the warships it built soon afterwards were modelled on these prizes.1 source1 source

On 12 February 1661 an Omani squadron, joined by the Sultan of Pate, appeared off Mombasa. Its soldiers sacked the town for about six weeks but left the fort alone. Civil strife in Oman then held back further attacks until the 1690s, when a new imam, Saif bin Sultan, came to power.1 source1 source

In October 1694 Goa heard that Pemba, the island that fed Mombasa, had rebelled and called in the Omanis. A new governor, João Rodrigues Leão, an old soldier, put the revolt down and warned that Oman would return in strength. The viceroy, the Count of Vila Verde, sent him one galliot of supplies and a reassurance: a Portuguese fleet in the Persian Gulf would keep the Omanis busy at home.1 source1 source

Accounts from the coast tell it differently. Mombasa's own Arabic chronicle, copied for the British naval officer William Owen in the 1820s, says the coast people could not bear Portuguese “oppression and tyranny” and complained to the imam of Oman, who came and drove the Portuguese from the fort. Swahili loyalties were split, though: Pate and Lamu sided with Oman, while the Queen of Zanzibar and refugees from Faza, Malindi and Kilifi stood by Portugal.2 sources2 sources

Rodrigues Leão's orders said only Christians were to be let into the fort in a crisis. With fifty Portuguese soldiers, he ignored them. Swahili refugees from Faza, Malindi and other towns who lived in Mombasa were trusted and let in, with the non-combatants crowded into the moat. The chronicle counts about 2,500 armed men in the fort and some 3,000 people in the moat.1 source1 source

The Omanis had no siege artillery. They mounted guns taken from the small outlying forts, which did little harm to the walls. Food came in by night from the Nyika, the peoples of the mainland, in exchange for cotton cloth. On 25 August 1696 the Omani commander sailed home with most of his army and a load of ivory, leaving about 900 men to keep up the blockade.1 source1 source

The defenders now outnumbered the besiegers, with fewer than 100 Portuguese but at least 1,500 armed Swahili. They made sorties but did not try to drive the besiegers away. Rodrigues Leão, who stood watch on the ramparts day and night, died of fever on 23 October 1696. The seventeen-year-old Prince of Faza, who placed himself wherever the fighting was worst, was killed in action. His cousin, Prince Dau, took his place.1 source1 source

Then disease took over. After the first relief ships left in January 1697, the Nyika stopped sending food, and people in the fort and the moat began to die fast. Boxer, following the chronicle, writes of plague; later arrivals died of beriberi. By early June 1697 only four Portuguese were alive: the governor, António Mogo de Melo, the Augustinian prior and two others.2 sources2 sources

Before dawn on 20 July 1697 the Omanis made their first assault on the walls. They were driven back with about eighty dead, and Prince Dau and some of the women did much of the fighting. Mogo de Melo died on 28 August. The garrison was now seventeen Swahili, four Africans, a few women and one Portuguese, a boy of eleven.1 source1 source

Prince Dau refused every offer of honourable surrender, in what the chronicle calls “short, dry, and resolute words”. Later, in Goa, Dau explained himself to the king.1 source1 source

Help was slow. The Queen of Zanzibar sent food throughout the siege, though most of it was intercepted and the Omanis sacked her own town. Goa heard of the siege only in September 1696 and fitted out a squadron under Luís de Melo de Sampaio, an India-born nobleman of poor reputation.2 sources2 sources

He reached Mombasa on Christmas Day 1696, when only twenty Portuguese were left alive in the fort. His orders were to land men and stores, not to enter Kilindini harbour, where the Omani ships lay. He landed about ninety men in a month and sailed away on 25 January 1697.1 source1 source

He came back on 16 September 1697 and, pushed by his lieutenant-commander José Pereira de Brito, brought the frigate Santo António de Tanná into the channel under the fort. On 20 October her cables parted, by gunfire or accident, and she drifted ashore and was lost; a sortie rescued the 150 men still aboard. Melo de Sampaio died of fever on 19 November. Pereira de Brito, a sailor who had risen from deck-hand, then led sorties that destroyed most of the Omani batteries.2 sources2 sources

A new squadron under Francisco Pereira da Silva reached Mombasa on 28 December 1697. The leaders in the fort begged him to sail into Kilindini and destroy the Omani ships while they attacked from the land side. He refused, saying his orders were to land supplies. When one of his boats was taken, the Omanis came up to the walls and read the captured orders from Goa aloud “in good Portuguese”, mocking them.1 source1 source

He left behind a new governor, Leonardo Barbosa Soutomaior, brave but brutal, who soon alienated the Swahili. Prince Dau and most of the Swahili and African defenders left, some on the frigates. Pereira de Brito sailed too. The squadron took off more than 400 women still alive in the moat and left on 19 January 1698, and Fort Jesus was on its own.1 source1 source

Goa had only rumours of how the fort fell until 29 October 1701, when an Indian named Brás Fialho arrived there. He had been a servant of the master of the lost Santo António de Tanná, had been taken prisoner and had escaped from Oman by way of Persia and Bombay.1 source1 source

By 12 December 1698, he said, the governor was very ill. The only others alive in the fort were eight Portuguese soldiers, three Indians, two African women and the captain's young slave. Barbosa sent the boy out to gather herbs, and when the boy said the Arabs would catch him, the governor snapped back.1 source1 source

The boy was caught. After dark the attackers climbed the walls in two places, and the defenders fell back to the bastion of Santo António, where they held out until seven in the morning of 13 December, the feast of Saint Lucy. The governor went out with a blunderbuss and was shot down. The rest surrendered.1 source1 source

Fialho also said two Portuguese soldiers, who had offered to show the victors the fort's treasure, led them into the church and the storehouse and blew up the gunpowder, killing themselves and more than 200 Arabs. Boxer doubts some details, since the church was found standing when the Portuguese returned thirty years later, but Arab and Swahili traditions tell a similar story.1 source1 source

The date has support from both sides. A Jesuit in Goa recorded 13 December, and an Omani war song in honour of Imam Saif, recorded by the French naval officer Charles Guillain, gives 9 Jumada II 1110 in the Islamic calendar: 13 December 1698, though Guillain converted it as the 14th.2 sources2 sources

Pereira da Silva's second fleet, with orders this time to force the harbour whatever the risk, sighted Mombasa within days and saw the red flag of Oman over the fort. The Omanis had hung white cloths over the damaged walls, and he concluded that the fort had fallen long before and been repaired. He did not go closer, and sailed on to Zanzibar and back to Goa.1 source1 source

Nobody knows exactly how many died. The chronicle puts Portuguese losses at about 1,000, with 2,500 Swahili fighters and some 3,000 of their dependants who died in the moat. The viceroy, writing to the king a year after the fall, gave higher figures. Boxer warns that there is no way of checking them. The attackers' losses were lower, but nobody estimated them reliably.1 source1 source

Both counts come from the Portuguese side. The Omani historian Ibn Ruzayq, writing in the nineteenth century, gives no figures: he records only that Imam Saif bin Sultan attacked the Christians and took Mombasa, Pemba and Kilwa from them.2 sources2 sources

Portugal tried to get Mombasa back. The Lisbon squadron of 1699 got no further than Mozambique, and a larger fleet gathered at Goa was wrecked or crippled by a hurricane on the night of 9 to 10 December 1701. The Swahili towns one by one accepted Omani overlordship, though in 1710 Mombasa reportedly had a garrison of only fifty Omanis.1 source1 source

The chance came during a civil war in Oman. In 1728 the Sultan of Pate, who had turned against the Omanis, helped a Portuguese fleet back into Mombasa. Rebel slaves had seized the fort from its Omani garrison, and on 16 March 1728 it was handed to the Portuguese. The new governor, Álvaro Caetano de Melo e Castro, quarrelled with nearly everyone. After the town rose against him in April 1729 he surrendered in October, and on 26 November sailed away with thirty men; most of the rest deserted.2 sources2 sources

A fleet of five ships and 1,250 men sent to retake the fort looked at it from a distance on 2 February 1730, saw the Omani flag and sailed on to Mozambique. On the way back to Goa a storm sank two of its ships; the flagship went down with its commander and 557 men. Apart from a failed attempt from Mozambique in 1769, Portugal never tried again.1 source1 source

Oman ruled Mombasa through governors from the Mazru‘i clan. When the Busa‘idi dynasty replaced the Ya‘rubis in Oman in the eighteenth century, these governors were a holdover from the old regime, and the new rulers set about bringing the East African ports back under their own authority.1 source1 source

From 1837 to 1895 the fort was used as barracks. When Britain proclaimed its East Africa Protectorate on 1 July 1895, the fort became a prison, and cells were built inside it.1 source1 source

On 24 October 1958 it was declared a national park. Excavations followed, and in 1962 it opened as a museum, built with a grant from the Calouste Gulbenkian Foundation of Lisbon, which also paid for the research behind Boxer and Azevedo's history of the fort.2 sources2 sources

The wreck of the Santo António de Tanná was excavated between 1977 and 1979 by the Institute of Nautical Archaeology and the National Museums of Kenya. Her guns turned out to be lighter and fewer than expected for a frigate of her size.1 source1 source

In 2011 UNESCO inscribed Fort Jesus on the World Heritage List under criteria (ii) and (iv), as an example of Renaissance military architecture and of exchanges between peoples of African, Arab, Turkish, Persian and European origin. The protected property covers 2.36 hectares, including the moat.2 sources2 sources

Today the sea threatens the walls. In 2018 the National Museums of Kenya told Lusa, the Portuguese news agency, that waves were eating into the coral rock under the walls, and that Kenya was investing about 500 million shillings, around €4.3 million, in a protective sea wall six metres out. Portugal, which had just resumed diplomatic representation in Kenya, offered its expertise in conservation.1 source1 source

For Portugal the siege ended its hold on the coast north of Mozambique, apart from 1728 and 1729. Kenya remembers it in its own way. Its World Heritage nomination praises the defenders' endurance, and UNESCO calls the fort a place of resistance for the coast's Swahili against domination by any power. In 2018 a museum educator in Mombasa told Lusa that local people regard the fort as theirs, part of the making of Kenya.4 sources4 sources