First, for their neighbors, there can no general rule be given (the occasions are so variable), save one which ever holdeth; which is, that princes do keep due sentinel, that none of their neighbors do overgrow so (by increase of territory, by embracing of trade, by approaches, or the like), as they become more able to annoy them than they were; and this is generally the work of standing counsels to foresee and to hinder it. During that triumvirate of kings, King Henry the Eighth of England, Francis the First, King of France,[217] and Charles the Fifth, Emperor, there was such a watch kept that none of the three could win a palm of ground, but the other two would straightways balance it, either by confederation, or, if need were, by a war; and would not, in any wise, take up peace at interest; and the like was done by that league (which Guicciardini[218] saith was the security of Italy) made between Ferdinando, King of Naples, Lorenzius Medicis, and Ludovicus Sforza, potentates, the one of Florence, the other of Milan. Neither is the opinion of some of the schoolmen to be received, that a war cannot justly be made, but upon a precedent injury or provocation; for there is no question, but a just fear of an imminent danger, though there be no blow given, is a lawful cause of a war. For their wives, there are cruel examples of them. Livia is infamed[219] for the poisoning of her husband; Roxolana, Solyman’s wife,[220] was the destruction of that renowned prince, Sultan Mustapha, and otherwise troubled his house and succession; Edward the Second of England’s Queen[221] had the principal hand in the deposing and murder of her husband. This kind of danger is then to be feared chiefly when the wives have plots for the raising of their own children, or else that they be advoutresses.[222] For their children, the tragedies likewise of dangers from them have been many; and generally the entering of fathers into suspicion of their children hath been ever unfortunate. The destruction of Mustapha (that we named before) was so fatal to Solyman’s line, as the succession of the Turks from Solyman until this day is suspected to be untrue, and of strange blood; for that Selymus the Second was thought to be supposititious.[223] The destruction of Crispus, a young prince of rare towardness, by Constantinus the Great, his father, was in like manner fatal to his house; for both Constantinus and Constance, his sons, died violent deaths; and Constantius, his other son, did little better, who died indeed of sickness, but after that Julianus had taken arms against him. The destruction of Demetrius,[224] son to Philip the Second of Macedon, turned upon the father, who died of repentance. And many like examples there are; but few or none where the fathers had good by such distrust, except it were where the sons were up in open arms against them; as was Selymus the First against Bajazet, and the three sons of Henry the Second, King of England.