Latest / The History of Portugal: The Small Nation That Built a Global Empire — Fexingo History / Siege of Diu 1538: Ottoman-Portuguese Battle for Indian Ocean
Transcript
- Lucas: So we've talked a lot about how Portugal built this web of fortified trading posts across the Indian Ocean — Goa, Malacca, Hormuz. But there was a moment in the 1530s when it all almost collapsed. And it came from an unexpected direction. Luna: The Ottomans? I've heard they challenged the Portuguese in the Red Sea. Lucas: Exactly. The Ottoman Empire had expanded into the Middle East and North Africa, and by the early 1500s they controlled the Red Sea. They saw the Portuguese monopoly on the spice trade as a direct threat to their own commerce and to Muslim pilgrims traveling to Mecca. So in 1538, they launched a massive expedition to drive the Portuguese out of the Indian Ocean altogether. Lucas: The target was Diu — a small island fortress off the coast of Gujarat, in modern-day western India. Diu was Portugal's key stronghold in the region, controlling trade with the powerful Sultanate of Gujarat. The Ottomans allied with Sultan Bahadur Shah of Gujarat, who had his own grievances with the Portuguese. Luna: Wait, wasn't Bahadur Shah the one who signed a treaty with the Portuguese? Lucas: Yes, but it was a tense relationship. In 1535, Bahadur Shah was fighting the Mughals and agreed to let the Portuguese build a fortress at Diu in exchange for military support. But once the Mughal threat passed, he realized he'd given the Portuguese a permanent foothold. He tried to negotiate their withdrawal, but the Portuguese governor Nuno da Cunha refused. So Bahadur Shah turned to the Ottomans for help. Lucas: The Ottoman sultan Suleiman the Magnificent saw the opportunity. He dispatched a fleet of over 70 ships commanded by Khadim Suleiman Pasha, a veteran eunuch general. They carried thousands of soldiers, heavy siege cannons, and the latest gunpowder technology. It was the largest naval expedition the Ottomans had ever sent into the Indian Ocean. Luna: How many men were we talking about? Lucas: Estimates vary, but around 20,000 Ottoman troops plus several thousand Gujarati allies. Against them, the Portuguese garrison at Diu numbered only about 600 men under the command of Captain Francisco de Menezes. They were vastly outnumbered, but they had one advantage: the fortress itself. Lucas: The fort of Diu was a state of the art stone fortress, built with angled bastions to resist cannon fire. The Portuguese had been improving it for years. And they had about 60 cannons mounted on the walls. The Ottomans arrived on September 4, 1538, and immediately began a siege that would last nearly three months. Luna: What was the Ottoman strategy? Just bombard the walls? Lucas: Initially, yes. They brought enormous bronze cannons that could fire stone balls weighing over a hundred pounds. They set up batteries on the island and on the mainland, bombarding the fortress day and night. But the Portuguese walls held. The Ottomans tried to mine under the walls, but the Portuguese counter-mined. They also attempted assaults across the moat, but were repelled with heavy losses. Lucas: Meanwhile, the Portuguese defenders were suffering too. Disease and dwindling supplies took a toll. Captain Menezes was killed in the fighting. But his second-in-command, João de Castilho, took over and kept the defense going. The garrison fought with a desperation that comes from knowing there's no escape. Luna: Did the Portuguese back in Goa know what was happening? Lucas: Yes, and they scrambled to assemble a relief force. The governor, Nuno da Cunha, gathered a fleet of about 30 ships in Goa, but he was cautious — he didn't want to risk everything in one battle. He sent a smaller squadron under Dom João de Castro to probe the Ottoman blockade. Castro was a brilliant naval commander, and he managed to sneak into Diu in October with reinforcements and supplies. Lucas: That relief was crucial. It boosted morale and gave the defenders fresh gunpowder and food. But the siege continued. The Ottomans tried a final massive assault in November, using scaling ladders and sappers to breach the walls. The fighting was hand-to-hand on the ramparts. According to Portuguese accounts, the defenders fought with such ferocity that the Ottomans eventually pulled back, leaving hundreds dead. Luna: So the Ottomans just gave up? Lucas: Not exactly. By early November, the monsoon season was ending, and the Ottoman fleet was suffering from disease and low morale. Suleiman Pasha also learned that a larger Portuguese relief fleet was on its way from Goa. Rather than risk being trapped, he decided to lift the siege on November 5, 1538, and sailed back to the Red Sea. It was a strategic retreat, but it was also a clear defeat. Luna: So the Portuguese held Diu. What did that mean for the bigger picture? Lucas: It was a turning point. The Siege of Diu confirmed Portuguese naval dominance in the Indian Ocean for another century. It showed that the Estado da Índia could defend its key positions even against a major power like the Ottomans. For the Ottomans, it was a humiliating failure. They never again attempted such a large-scale expedition to challenge the Portuguese in India. Lucas: The victory also had a personal dimension. Dom João de Castro, who had led the relief, became a hero. He later became Viceroy of India and is remembered as one of Portugal's greatest colonial administrators. And the fortress of Diu remained in Portuguese hands until 1961, when India finally annexed it. Luna: That's incredible — a tiny garrison holding out against a huge army. What was the key factor? Technology? Leadership? Lucas: Both. The Portuguese had superior fortification design, better naval tactics, and a culture of discipline and desperation. But also, the Ottomans underestimated the difficulty of sieging a well-supplied fortress from the sea. They couldn't completely blockade the port, so the Portuguese could still receive supplies. And they faced the monsoon, which limited their time. It was a combination of strategy, luck, and sheer stubbornness. Luna: And Bahadur Shah? What happened to him? Lucas: After the siege failed, Bahadur Shah was in a difficult position. He had openly allied with the Ottomans against the Portuguese, but now his powerful neighbor was gone. He tried to negotiate with Nuno da Cunha, but the Portuguese were wary. In February 1537, just before the siege, Bahadur Shah had been killed during a meeting with Portuguese officials — some say in a scuffle, others say he was assassinated. His death left Gujarat in chaos, and the Portuguese took advantage to strengthen their control. Luna: So the Ottomans never came back in force? Lucas: Not in a major way. They continued to contest the Portuguese in the Red Sea and the Persian Gulf, and they supported local rulers like the Sultan of Aceh in Sumatra against the Portuguese. But after Diu, the Indian Ocean remained a Portuguese lake until the arrival of the Dutch and English in the 1600s. Lucas: The siege is also a great example of how global the 16th century was. You had Portuguese from Europe, Ottoman Turks, Gujarati Muslims, even some Ethiopian Christians fighting on the Portuguese side. It was a clash of empires that shaped the modern world. Luna: It really puts the 'global' in global empire. Thanks for that story, Lucas. Lucas: You're welcome. It's one of my favorite episodes in Portuguese history — a David and Goliath story with real consequences. Next time, we might look at how Portugal managed to hold onto its empire as new powers rose.