Scarce map of the fortified town of Diu, India, which appeared in Francois de Belleforest's Cosmographie Universelle De Tout le Monde.
The town and district of Diu was part of the Saurashtra region of Gujarat and an important port on trade routes of Arabian sea of Indian Ocean.
Diu was the site of the Battle of Diu in 1509 between Portugal and a combined force of Turkey, Egypt, Venice, the Republic of Ragusa and the Sultan of Gujarat, Mahmud Begada. In 1513, the Portuguese tried to establish an outpost there, but negotiations were unsuccessful. There were failed attempts by Diogo Lopes de Sequeira in 1521, Nuno da Cunha in 1523. In 1531, the conquest attempted by D. Nuno da Cunha was also not successful.
In 1535 Bahadur Shah, the Sultan of Gujarat, concluded a defensive alliance with the Portuguese against the Mughal emperor Humayun, and allowed the Portuguese to construct the Diu Fort and maintain a garrison on the island.
The alliance quickly unraveled, and attempts by the Sultans to oust the Portuguese from Diu between 1537 and 1546 failed. Having repented of his generosity, Bahadur Shah sought to recover Diu, but was defeated and killed by the Portuguese, followed by a period of war between them and the people of Gujarat. In 1538, Coja Sofar, lord of Cambay, together with the Turkish Suleiman Pasha of Ottoman Empire, came to lay siege to Diu, and were defeated by Portuguese resistance led by Anthony Silveira. A second siege was imposed by the same Coja Sofar, in 1546, and repelled by the Portuguese conquerors, led on land by D. John Mascarenhas, and at sea, by D. João de Castro. Coja Sofar and D. Fernando de Castro, son of the Portuguese viceroy, perished in the struggle. The fortress, completed by Dom João de Castro after the siege of 1545, still stands.
After this second siege, Diu was so fortified that it could withstand later attacks of the Arabs of Muscat and the Dutch in the late 17th century. From the 18th century, Diu declined in strategic importance, due to development of Bombay and came to be reduced to a museum or historical landmark as commercial and strategic bulwark in the struggle between the forces of the Islamic East and Christian West.