By 1648, Portugal's once-formidable grip on Oman had withered to three coastal outposts: Muscat, Muttrah, and Khasab. The Yarubid dynasty, under the leadership of the Omani Imam Nasir bin Murshid, had systematically recaptured the rest. Portuguese garrisons that had dominated the Gulf of Oman trade routes for over a century now found themselves besieged, outnumbered, and increasingly desperate. The two great fortresses of Muscat -- Sao Joao and Capitao, perched on rocky headlands overlooking the harbor -- remained formidable, but the men inside them were running out of ammunition, food, and hope. A plague struck the garrison. When peace negotiations finally produced a treaty in October 1648, the terms were humiliating enough to outrage the king in Lisbon, who ordered the captain of Muscat arrested.

In April 1649, Nasir bin Murshid died and was succeeded by Sultan bin Saif. The new Imam wasted no time. His first act was to prepare for the final assault on Muscat. He gathered his forces at Tuwa al-Rowla, near Muttrah, and moved them into Sayh Harmal. The initial attacks against the Portuguese positions at Bir al-Rawiya failed under withering fire, and the Imam pulled back to reconsider. The Portuguese used the pause to retreat into their two main fortresses. The Omanis pursued and laid siege, challenging the garrison to single combat. According to the Omani narrative, no one inside accepted.

What happened next turned on a personal grievance. Narottam, an Indian officer working in the castle storehouse, sabotaged the gunpowder supply on the Imam's orders. While Portuguese soldiers marked Christmas in celebration, Sultan bin Saif launched his assault after the dawn prayer. His men scaled the walls and fought through the fortress. One Portuguese officer named Cabreta mounted fierce resistance but was driven back to the shops near the waterfront, where he was killed. The garrison was nearly wiped out. Portuguese sources record that around 700 inhabitants fled to Diu by January 18, and only 60 or 70 of the garrison survived, later converting to Islam and integrating into Omani society. The Omanis, too, paid a steep price -- between 4,000 and 5,000 of their fighters died in the siege.

The fall of Muscat ended more than a century of Portuguese rule in Oman and effectively expelled them from the Persian Gulf. They clung to one small base at Khasab until 1655, and a fleet dispatched from Goa in 1652 to recapture Muscat failed entirely. For Oman, the victory marked a transformation. The sultanate pivoted from defensive resistance to maritime expansion. The naval power born from this triumph would grow over the following decades, projecting Omani influence across the Indian Ocean and culminating in the capture of Mombasa from the Portuguese in 1698. The twin fortresses of Sao Joao and Capitao still stand above Muscat harbor, now known as Al Jalali Fort and Al-Mirani Fort, monuments to the centuries when two empires contested this narrow strip of Arabian coast.