The royal European courts were unsurpassed for their glamour, wealth, fame, danger, treachery, and politics. The royal mistress was at the center of that world -- admired for her beauty and sensuality; feared for the power she wielded; even vilified, envied, and resented. In times when women had very little power, the royal mistress had enormous influence, and yet she is seldom mentioned in official histories. In Cupid and the King, Her Royal Highness...