The campaign of 1492 was glorified blackmail. Henry secured a very generous war grant from Parliament, and then, in the very week when Columbus reached America, crossed to France with some twenty-seven thousand men. He laid siege to Boulogne, not because he particularly wanted it, but because he knew that France was so busy in preparing to invade Italy that she would not want to be bothered with an English war. To the gratification of Henry and the disgust of his army, he was bought off before any serious bloodshed occurred. The royal treasury was consequently richer both by the expended balance of the Parliamentary grant and by the French bribe.
(from A History of England and the British Empire)