This was one of the most important junctures of Philip’s life. He was barely sixteen years old, and was thus early to be entrusted with Charles’s secret system of government, an instruction which left deep marks upon Philip’s own method for the rest of his life. The two letters written by Charles to his son before his departure from Spain are of the utmost importance as providing a key for Philip’s subsequent political action. Although Philip was entrusted with the ultimate decision of all subjects, he was to be guided by some of the most experienced and wisest of Charles’s councillors. First there was the Cardinal-Archbishop of Toledo, Tavara, and next the Secretary of State, Francisco de los Cobos, who had been at the emperor’s right hand for so long. The young regent is secretly told by his father that the reason why these two were appointed as his principal councillors was because they were respectively heads of factions, and their rivalry would prevent the prince from falling under the influence of either political party. With merciless scalpel the great emperor lays bare, for the benefit of the lad of sixteen, the faults and failings of the statesmen who are to aid him in the government. He is warned not to trust any of them separately. Their hypocrisy, their greed, their frailties of character, and conduct are pointed out by the worldly-wise ruler to the neophyte; and the moral of it all is that he should listen to the opinions of every one, and especially of rivals, and then decide for himself.