Latest / The History of Portugal: The Small Nation That Built a Global Empire — Fexingo History / The Portuguese Fortress of Diu: Siege, Spice, and Survival
Transcript
- Lucas: So, we've covered a lot of Portuguese India — Vasco da Gama's first voyage, the spice monopoly, the rise of Goa. But there's one place that really became the linchpin of their whole Indian Ocean strategy, and it's not Goa. It's Diu. Luna: Diu — the island fortress off the coast of Gujarat, right? Lucas: Exactly. A tiny island, barely 40 square kilometres, but it controlled access to the Gulf of Khambhat — which was the gateway to all the trade of northern India. The Portuguese got their foot in the door there through a classic imperial move: they played rival powers off each other. Lucas: In 1535, the Sultan of Gujarat, Bahadur Shah, was facing an invasion from the Mughal emperor Humayun. He desperately needed Portuguese naval support. So he offered them permission to build a fortress at Diu. The Portuguese jumped at it. Luna: A fortress that would become the symbol of their power in the region. Lucas: But Bahadur Shah's deal came back to haunt him. Once the Mughal threat receded, he tried to renegotiate — and the Portuguese refused to give up the fortress. Tensions escalated, and in 1537, Bahadur Shah was killed in a skirmish with the Portuguese. That set the stage for the biggest crisis the Estado da Índia ever faced. Lucas: Because the Ottomans had been watching. They had their own ambitions in the Indian Ocean — they'd already established a presence in Aden and Basra, and they saw the Portuguese fort at Diu as a direct threat to their control of the spice routes to the Red Sea and the Mediterranean. Luna: So the Ottomans decided to drive them out. Lucas: In 1538, Suleiman the Magnificent ordered a massive expedition. He put together a fleet of about 80 ships — galleys, galleons, transport vessels — carrying maybe 20,000 men. The commander was Hadim Suleiman Pasha, one of his most experienced governors. And they had local allies, too — the new Sultan of Gujarat, who wanted revenge for Bahadur Shah's death. Lucas: On the Portuguese side, the fortress of Diu was commanded by a captain named António da Silveira. He had maybe 600 Portuguese soldiers, plus a few hundred local auxiliaries. And the fortress itself was still incomplete. Luna: So they were massively outnumbered. How did they even have a chance? Lucas: A few things. First, the fortress was built on a narrow spit of land, with the sea on three sides. It had thick walls, a deep moat, and bastions that could cover every approach. Second, Silveira was an experienced soldier — he'd fought in North Africa and knew how to manage a siege. Lucas: But the biggest factor was the monsoon. The Ottoman fleet arrived in September, right at the end of the monsoon season. That meant they couldn't maintain a close blockade — the sea was too rough for their galleys to stay offshore. So they had to attack by land. Luna: Which played right into the fortress's strengths. Lucas: Exactly. The Ottomans set up artillery batteries on the mainland and began a bombardment that lasted for weeks. They tried to fill the moat with rocks and rubble, then assault the walls. But every time they got close, Portuguese cannon fire — and arquebus fire from the bastions — cut them down. Lucas: There's one famous incident: the Ottomans managed to breach the outer wall, and a group of Janissaries rushed in. But Silveira had prepared a second defensive line, and his men counter-attacked, driving them back. The Janissaries were elite troops, but in that confined space, they couldn't use their superior numbers. Luna: And what about the Portuguese relief fleet? Lucas: That was the other key. The Portuguese governor in Goa, Nuno da Cunha, had been gathering a relief force. He sent a fleet of about 50 ships under the command of his nephew, also named Nuno da Cunha. They arrived in early November, just as the Ottomans were preparing a final assault. Lucas: The sight of Portuguese sails on the horizon was enough. The Ottoman fleet — which had already suffered from disease and desertion — decided to withdraw. They sailed back to Suez, leaving the fortress intact. The siege had lasted about a month. Luna: It must have been a huge morale boost for the Portuguese. Lucas: Enormous. Diu became a symbol of Portuguese invincibility. They called it the 'Key to India'. And they held it for over 400 years — until 1961, when India annexed it. Lucas: But the siege also had wider consequences. It marked the high point of Ottoman naval ambition in the Indian Ocean. After this failure, the Ottomans never again attempted a major expedition that far east. They turned their attention to the Mediterranean instead. Luna: So the Portuguese basically won control of the Indian Ocean spice routes right there. Lucas: That's the argument. Diu, along with Goa and Malacca, formed a triangle of fortresses that let the Portuguese dominate trade for the next century. And it all hinged on that one siege — where a few hundred men held out against an empire. Lucas: You know, thinking about stories like this — where a small, determined group changes the course of history — it reminds me why we do this show. And if you find this kind of deep dive useful, the way we keep it ad-free is through listener support. You can help at buy me a coffee dot com slash fexingo. Luna: Yeah, it's a small way to keep these conversations going. And we really appreciate it. Lucas: Anyway, back to Diu. After the siege, the Portuguese massively reinforced the fortress. They built it up into one of the strongest in Asia — with walls up to 12 metres thick in places. You can still see it today, though it's now a tourist site. Luna: I've seen pictures — those massive stone walls and the old cannons pointing out to sea. It looks formidable. Lucas: It is. But the really interesting part is how Diu functioned as a commercial hub. The Portuguese didn't just control it militarily — they turned it into a customs house for all the trade passing through the Gulf of Khambhat. Every ship had to stop and pay duties, or risk being sunk. Lucas: And they used the cartaz system — a kind of naval passport — to enforce their monopoly. Any ship without a cartaz was considered a pirate. That system, combined with fortresses like Diu, let them control the flow of spices, textiles, and even horses into India. Luna: Horses? I didn't know horses were a big trade item. Lucas: Huge. The Indian kingdoms needed warhorses, but India doesn't have great grazing land for them. So they imported them from Arabia and Persia — and the Portuguese controlled the sea routes. At Diu, they taxed every horse that came through. It was incredibly profitable. Lucas: So Diu wasn't just a fortress — it was a machine for extracting wealth. And it stayed that way for centuries, long after the Portuguese empire had declined elsewhere. Even in the 20th century, it was still a Portuguese enclave, with its own distinct culture. Luna: There's a mix of Portuguese and Gujarati architecture there, right? I've seen photos of those whitewashed churches and the old Portuguese houses. Lucas: Exactly. The Church of St. Paul's, built in the 1600s, and the Diu Fort itself, with its lighthouse. It's a living museum of the Portuguese presence in India. And the local cuisine — like the seafood dishes — has Portuguese influences too. Lucas: So Diu is a reminder that empire wasn't just about battles and treaties. It was about everyday life — trade, culture, food. And that legacy is still visible today. Luna: It's amazing how a single island could have such an outsized impact on world history. Lucas: Absolutely. The Siege of Diu was a turning point. It secured Portuguese dominance in the Indian Ocean for another century, and it shaped the way European empires operated in Asia. Next time, we might look at another key fortress in their network — maybe Malacca, or Hormuz. Luna: I'd love that. Hormuz especially — I've heard it was the key to the Persian Gulf. Lucas: It was. But that's for another episode. For now, we leave you with the image of those few hundred Portuguese soldiers on the walls of Diu, watching the Ottoman fleet sail away — and knowing they'd just changed history.