Q. The Battle of Diu in 1509 was a significant naval engagement fought between the Portuguese and which combined forces?
Answer: The Portuguese and a combined fleet of the Mamluks and the Gujarat Sultanate
Notes: The 1509 Battle of Diu saw the Portuguese defeat a coalition of the Gujarat Sultanate, Mamluks (Egyptians), Zamorin of Calicut, and others, solidifying Portuguese naval dominance in the Indian Ocean and establishing their colonial foothold in India.