The city of Havana was founded by the Spanish in the 16th century and due to its strategic location it served as a springboard for the Spanish conquest of the continent, becoming a stopping point for treasure-laden Spanish galleons returning to Spain. King Philip II of Spain granted Havana the title of City in 1592. Walls as well as forts were built to protect the old city. The sinking of the U.S. battleship Maine in Havana's harbor in 1898 was the immediate cause of the Spanish–American War.