No one knows exactly when it was built, or by whom. Now a member of Fujairah's ruling family has made it his mission to document as much as is possible about a building that once housed his ancestors and played host to weddings and executions.
Perched high on a hill, it was once the centre of Fujairah, a sentry and a home, and has seen peaceful times and periods of strife. It has housed a prison and a room devoted to fermenting date syrup, and withstood attack by British naval forces and occupation by Wahabbists. Now the historic landmark has opened its gates to the public in a revival of the pivotal role it once played.
The sand-coloured fort overlooks the remains of at least 40 mudbrick houses. Behind it, far in the distance, are the tall buildings of modern-day Fujairah.
"It is a walk through time," said Sheikh Abdullah bin Suhail Al Sharqi, a businessman and member of the ruling family of Fujairah, who has taken a keen interest in the history of the fort - he has even publishing papers on the subject.
The fort, which changes colour between deep orange and light brown depending on the location of the sun, opened to the public for the first time last month, when it played host to a traditional sword competition. After seeing how much interest there was in the building, authorities decided to open it permanently and are working on plans to replace some of its original artefacts, such as cannons.
"It is about putting all the pieces together again and telling the history of this place to the current and future generations," said Sheikh Abdullah, 42.
The fort is made of rocks, mortar, mud and plaster, and is shored up by mangrove poles. Its roof is made of palm fronds and trunks. It covers an area of 610 square metres, and features circular watch towers, one each facing the sea, the town and the mountains - and one main, square-shaped tower, known as a Murabaa. Each tower reaches more than 2.5 metres above the top of the walls.
Like most other such buildings, Fujairah's fort was constructed around a well, though the well went dry a long time ago. The courtyard was used for special events, such as weddings or public executions.
Taking a walk inside the Murabaa, Sheikh Abdullah points out the most likely use of each of the four three-by-seven metre rooms.
"Here is the prison, where prisoners would be lowered into the ditch," he said, pointing to the hole. "We believe it stopped being a prison sometime in the early 1900s, as we have saved testimonials of guards who once worked here."
Next to the prison is another area with special channels carved into its floor, all flowing towards a hole, into which would run modabas, or date syrup. Sacks of dates would be piled up and left to ferment, and this would produce the juice.
Sheikh Abdullah's continued interest in the fort stems from personal reasons.
"My ancestors lived here at some point," he said. "And so I wanted to find out the real story behind this fort, and realised just how difficult it is to get accurate facts."
One of the milestones in the building's history was a two-year occupation by Wahabbists, from 1808 to 1810. They took possession of the fort, as well as others along the Eastern Coast, until local tribes won it back.
The British navy destroyed one of the fort's towers in 1925 as it moved into the country and took up positions along the coast. The fort was abandoned after that, and remained in a state of neglect until 1997, when a national renovation programme began. The restoration was completed in 2000. A pamphlet published by the Fujairah Tourism and Antiquities Authority dates the fort to the 16th century, which would make it one of tens of other fortresses built by the Portuguese when they occupied areas along the Indian Ocean and the Arabian Gulf. Similar fortresses were built in Dibba, Bidiya, Khor Fakkan, and Kalba in the UAE, and in Oman.
But Sheikh Abdullah found a recent study made by a visiting Australian delegation that said carbon dating showed the fort was built about 1800, around the time of the rule of Sheikh Mohammad bin Matar Al Sharqi. "It is easy for wrong information to be passed down, as there aren't any reliable sources," Sheikh Abdullah said.
Dr Hasan al Naboodah, a historian at UAE University in Al Ain, said: "What we know from documents is that the Portuguese built the first forts here on the eastern coast of UAE and Oman, and then the ruling families built their own forts in other parts of the UAE."
When Dr al Naboodah wrote a chapter on forts in the book The Architecture of the United Arab of Emirates, published in 2006, he also had a hard time fixing dates to the existing forts.
"We know why they were built: for security during conflict, and administrative work during peace," he said. "But 'when' is always a big question."
Whatever its age, the fort remains a special place for the residents.
"My great-grandfathers' house was somewhere here," said Sheikha al Mesmari, 33, pointing to one of the areas near the fort where only the foundation of a house has survived.
"I am happy I can climb up on to the roof of the fort and see my ancestors' village and my current home," she said. "Regardless of how old it is, it is part of my history."
The Fujairah fort is open daily until 5pm, although hours may vary. Entrance is free.