For five centuries, since Vasco de Gama's ships began making the Indian Ocean a Portuguese lake, many governments used naval force to serve their political purposes. The sceptre of the seas passed from one nation to another, but political success did not always reward the strongest navy. This selective, international history of naval force as a political instrument, whether in peace or war, ranges from Calicut, navally cannonaded in 1501, to Baghdad, assailed by sea launched missiles in 1991.