
In 1699, the 450-ton, 50-gun English slave ship Speaker was captured by pirates off the coast of Madagascar. They elected as their captain one George Booth and headed for the East Indies, where the richest prizes were to be had at the expense of the Dutch East India Company. Before crossing the Arabian Sea, they stopped at Zanzibar to take on provisions. The Omani Arabs, who had seized the island from the Portuguese not long before, were no doubt suspicious of the appearance of a strange vessel. Captain Booth was ordered to present himself and a skirmish broke out in which he was slain. The rest of his party retreated to the beach to make for the ship, and an eye-witness account reports what followed:
‘The quartermaster ran down to the shore sword in hand, and though he was attacked by many, he behaved himself so sturdily that he managed to get into a canoe in which he put off and gained the long boat. In the interim the Arab fort played on the pirate ship which returned their salutes very warmly.’
This is the first we hear of an Omani fort in Zanzibar. The Old Fort still stands at the heart of Stone Town, the principal settlement of the island, renowned for its architecture, fusing Arab, Persian, Indian, and local Swahili cultural traditions into a unique Indian Ocean metropolis, on which basis it was inscribed on the list of UNESCO World Heritage Sites. It was rebuilt and expanded over the course of the 18th and 19th centuries, in particular by Sayyid Said, the Sultan of Oman, who moved his capital to Stone Town in 1840. That same year, in a remarkable meeting between two worlds, he despatched Ahmad bin Na‘aman al-Ka‘abi to New York to seek out an alliance with the emerging superpower.

Not much survives of the Omani garrison, however. In 1905, the modernising Sultan Ali bin Hamud demolished the intramural structures to install a terminus for the Bububu Railway. This was subsequently dismantled in 1930, leaving empty courtyards that the colonial British gave over for the recreation of ladies in purdah. Our three seasons of archaeological excavations between 2017 and 2022 discovered that any 18th- and 19th-century occupational activity that might once have existed was almost entirely absent. Fortunately, as we peeled away the thick layer of demolition debris we came down onto intact and undisturbed archaeological layers.
An Augustinian church
Our excavations were prompted, in part, by the curious origins of the Old Fort as gleaned from the historical sources. On 10 August 1710, the Portuguese Viceroy of Goa reported to the government at Lisbon that it had been constructed out of the remains of an Augustinian church. Somewhat later, in a British chart of 1774, it is described as a ‘fort or factory [trading station], where there is some small guns, which appears like a ruined church’. Indeed, there seems to be some communal memory of this transformation, for the Old Fort is known locally as the Gereza, an etymology perhaps derived from the Arabic word for church.

We realised, when recording the architectural elevations of the Omani fort, that the outlines of bricked-up windows and beam slots visible in the inner face of the seaward wall were the remains of the Portuguese church. This startling discovery led us to open trenches in the vicinity, which very soon started to reveal the architectural plan of a basilica church. The best parallels for this building are with the 17th-century Church of Santo António on the Island of Mozambique. Indeed, a Papal Bull of 1612 mentions the church of Zanzibar as part of the diocese of Mozambique, which later sources refer to as Nossa Senhora da Graça, ‘Our Lady of Grace’. We had discovered a lost church of the Portuguese Empire in Africa.
Soon, we started to find human remains: burials under the floor of the church. The first of these, found in 2017, was an intact inhumation burial of an individual wearing a Sacred Heart pendant. By 2022, we had excavated 18 individual burials. Many more fragments were found in pits, probably dug to dispose of human remains accidentally excavated during the construction of the Bububu Railway. DNA sampling and strontium analysis will be able to determine the ethnic origins and childhood homelands of the individuals buried in the cemetery. We have every reason to believe this will demonstrate a cosmopolitan community drawn from Africa, Asia, and Europe. The Portuguese colonial cemetery at Zanzibar thus presents us with a fascinating microhistory of the early-modern Indian Ocean world.

A Portuguese trading station
We found further evidence for the Portuguese factory (trading station) that historical sources suggest flourished between the 1570s and 1698. Part of the enclosure wall was revealed by a trench in 2017. This year, we opened a new trench and discovered three phases of walls spanning the 16th and 17th centuries. Finds from the factory excavations include Qing-dynasty porcelain from the mid 17th century, probably made in the world-famous Jingdezhen kilns in Jiangxi province in southern China during the reign of the Kangxi Emperor, when the Qing dynasty was at its peak. Interestingly, the Jesuits were active at the Qing court, and the Portuguese Jesuit, Thomas Pereira, served as a translator for the Emperor.
The Old Fort in Stone Town, Zanzibar, can now be shown to be one of the most remarkable buildings in East Africa. It began as a Portuguese trading station in the late 16th century; the success of this commercial settlement led to the appointment of a vicar and, by the 17th century, the construction of a church for the Augustinian mission – one of the largest ever founded in the southern hemisphere. This large stone building with thick walls was readily transformed into a fort by the Omani Arabs in the 18th century, who rebuilt and enlarged it when they shifted their capital to Zanzibar in the 19th century.
Timothy Power is an Associate Professor for Archaeology at the UAE University and Mark Horton is a Professor at the Cultural Heritage Institute of the Royal Agricultural University. Their research specialisations bring together the Arabian Peninsula and East Africa as part of a shared interest in the archaeology of the pre-modern Indian Ocean world. The 2022 field season was funded by the Dhakira Center for Heritage Studies at New York University Abu Dhabi and carried out in collaboration with the Ministry of Tourism and Heritage, Zanzibar.