Eight kings of England were the named Henry, but only two of them were born as heirs to the throne and these - the third and sixth - proved to be the weakest. Two seized the crown by force of arms, one by craft and opportunistic speed, and one by skilful diplomacy and an early flowering of that great British virtue, compromise. Among their number are saints and monsters, the best known and the least known of English kings. One was a storybook hero,...