Portuguese Empire years for the Portuguese to follow up on Dias's voyage to the Cape of Good Hope, though it has also been speculated that other voyages were in fact taking place in secret during this time. Whether or not this was the case, the long-standing Portuguese goal of finding a sea route to Asia was finally achieved in a ground-breaking voyage commanded by Vasco da Gama. The squadron of Vasco da Gama left Portugal in 1497, rounded the Cape and continued along the coast of East Africa, where a local pilot was brought on board who guided them across the Indian
Ottoman naval expeditions in the Indian Ocean against Portuguese attacks. In 1534, Suleiman annexed most of Iraq and by 1538 the Ottomans had reached Basra, i.e., the Persian Gulf. The Ottoman Empire still faced the problem of Portuguese controlled coasts. Most coastal towns on the Arabian Peninsula were either Portuguese ports or Portuguese vassals. Another reason for Turco-Portugal rivalry was economic. In the 15th century, the main trade routes from the Far East to Europe, the so-called spice route, was via the Red Sea and Egypt. But after Africa was circumnavigated the trade income was decreasing. While the Ottoman Empire was a major sea power in the