Beginning in 1659, as the King reached the age of twenty-one, and Mazarin approached the end of his life, he wrote a series of guidelines in political affairs for the King. When the King set off on his journey to Spain to be married, Mazarin wrote to him: "Remember, I ask you, what I have had the honor to tell you, when you asked me the way to take to become a great King...it is necessary to begin by making the greatest efforts to not be dominated by any passion...because, otherwise, if any misfortune arrives, regardless of what good will you have, you will not be able to do what has to be done."