Diu

The town and district were historically part of the Saurashtra region of Gujarat and an important port on trade routes of Arabian sea of Indian Ocean.

Due to its strategic importance, there was a Battle of Diu in 1509 between Portugal and a combined force of Mamluks, Venetians, the Ragusians, the Zamorin of Calicut, and the Sultan of Gujarat, Mahmud Begada. In 1513, the Portuguese tried to establish an outpost, but negotiations were unsuccessful. There were failed attempts by Diogo Lopes de Sequeira in 1521 and Nuno da Cunha in 1523. In 1531 the conquest attempted by D. Nuno da Cunha was unsuccessful.

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 unravelled, and attempts by the Sultans to oust the Portuguese from Diu between 1537 and 1546 failed. Regretting 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 Ottoman Suleiman Pasha, 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. It was repelled by the Portuguese conquerors, led on land by D. João 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 was reduced to a museum or historical landmark as a commercial and strategic bulwark in the struggle between the forces of the Islamic East and Christian West.

Diu remained a possession of the Portuguese from 1535 until 1961, when it fell to troops of the Indian Union, who invaded all of former Portuguese India under Operation Vijay. The island was occupied by the Indian military on 19 December 1961. The Battle of Diu involved overwhelming land, sea and air strikes on the enclave for 48 hours until the Portuguese garrison there surrendered. It was declared a union territory of India, Goa, Daman, and Diu. Goa separated as a state in 1987; the remainder became union territory of Daman and Diu. On 26 January 2020, the union territories of Daman and Diu were merged with Dadra and Nagar Haveli to form the union territory of Dadra and Nagar Haveli and Daman and Diu.