Why was Diu an important Portuguese fort and port?

Diu was a strategically vital location for the Portuguese because it served as a key port commanding the commercial and pilgrimage routes between India and the Middle East.12

Following the construction of a fort in 1535, Diu became a central point for enforcing Portuguese maritime authority in the region. By the mid-1550s, the Portuguese utilized the fort to control regional trade, requiring all Gujarati ships entering or leaving the Gulf of Khambhat to call at the port and pay duties. This control over shipping lanes was a fundamental component of the Portuguese effort to dominate Indian Ocean trade during the 16th century.12