As the king had sent orders to the governor to build forts at the Moluccas, Sumatra, Maldive, Chaul, and Diu, Sequeira determined upon attempting the last first.  Having dispatched the homeward ships from Cochin, he collected a fleet of 48 vessels of various kinds and sizes, on board of which he embarked 3000 Portuguese and 800 Malabars and Canarins.  With this great force he appeared before Diu on the 9th of February 1521.  Malek Azz, being suspicious that this armament was destined against him, had fortified and intrenched the city with great care.  At the arrival of the Portuguese, Malek Azz was at the court of Cambaya, but had left his son Malek Saca with a strong garrison and three experienced commanders.  Observing the strength of the place, Sequeira called a council of war to consult upon what was proper to be done, when it was concluded to desist from the enterprise.  The officers of the fleet, though they had all concurred in this decision, and even privately allowed its prudence and necessity, accused the governor of cowardice on this occasion, though his valour was well known.  Sequeira accordingly retired to Ormuz for the winter, sending Alexius de Menezes to Cochin with full power to conduct the government during his absence, and several of the other captains went to different ports to trade.  Menezes dispatched the homeward trade from Cochin, and sent other ships to various parts of India, some of which went to Sumatra.

The island of Sumatra extends in length from the north-west to the south-east, for about 220 leagues, by 70 in its greatest breadth, and is cut nearly in two equal parts by the equinoctial line.  It is separated from Malacca by a narrow strait, and its most southern point is parted from Java by one still narrower.  Java is above 100 leagues long by twelve in breadth.  To the east of Sumatra is the great island of Borneo, through which likewise the equinoctial passes, leaving two-thirds of the island on the north side of the line.  The maritime parts of Sumatra are flat, but the interior is full of mountains, pervaded by many large rivers, and covered by impenetrable woods which even the rays of the sun are unable to pierce.  Owing to these circumstances Sumatra is very unhealthy, yet is much resorted to for its rich and valuable productions, and particularly on account of its abounding in gold.  Besides gold, it produces white sandal-wood, benzoin, camphor, pepper, ginger, cinnamon[153], abundance of silk, and abounds in fish and cattle.  It has in one part a spring of petroleum or rock oil, and one of its mountains is a volcano.  The original natives of the island are pagans; but the Moors who came there first as merchants, have possessed themselves of the island as lords ever since the year 1400.  Among the inland tribes is one called Batas, who are of most brutal manners, and even feed on human flesh.  The Moors who dwell on the coast, use several languages, but chiefly the Malay.  Their weapons are poisoned arrows like the natives of Java from whom they are descended, but they likewise use fire-arms.  This island is divided into nine kingdoms; of which Pedier was once the chief; but now that of Pacem or Pisang is the most powerful, yet its kings only continue to reign so long as it pleases the rabble.