* The ruler of medieval Gujarat who surrendered Diu to the Portuguese was Sultan Bahadur Shah. Diu was an important port city strategically located on the western coast of India, and its surrender to the Portuguese in 1535 marked a significant event in the history of Portuguese colonial expansion in India. * This was done to seek Portuguese military assistance against his rival Humayun, the Mughal emperor. As a result, the Portuguese established a strong foothold in Diu, turning it into a significant strategic and trading post.