Before the Portuguese built the fortress in 1535, the ancient history of the place was linked to several kings and dynasties. The island was occupied by the
Chavda Rajputs in the 9th century, and later by the
Vaghela dynasty. The island would later come under the control of the
Gujarat Sultanate.
Sultan Bahadur Shah of Gujarat sought the help of the Portuguese when
Mughal Emperor Humayun was getting ready to attack Gujarat and annex Sultan's territory. The Portuguese thus got the right opportunity, which they were seeking for long, to get a foothold on the Diu island to build a fort for the protection of their trade. After the Portuguese ambition to build a fort at Diu was met, there was total mistrust between the Sultan and the Portuguese on several issues. In 1537, in Diu harbor, the Sultan was killed in a fracas with the Portuguese. This resulted in a fight for the throne of the
Sultanate of Gujarat by two claimants, but Governor Cunha's candidate lost. This put the Portuguese in a spot vis-a-vis the throne and they quickly repaired the damage by entering into a truce with the new Sultan, which was only a temporary reprieve. In 1670 an armed group of bandits from
Muscat pillaged the fort and the town. "
Operation Vijay" was launched by India on 19 December 1961 to end Portuguese rule in Goa, Daman and Diu. After Diu had fallen, the Martyrs Memorial was erected close to the Collectorate office in Diu to commemorate the Indian soldiers who were killed in the capture of Diu. ==Geography==