"Do not be too anxious to devote yourself to scientific studies, which both preoccupy the mind from more important subjects, and sadden it. Be satisfied with a thorough knowledge of your native tongue, so as to read in it all old and modern histories, and at fit times some devotional book; but trust to acquiring knowledge of the sciences from the discourse of their respective professors. It is advisable to learn other languages; indeed, Spanish is necessary, as you are in the service of his Catholic Majesty. "Practise all healthful exercises, especially, ball, hunting, and the manège. In the first of these you may indulge almost daily; for the second, once a week is sufficient, as it loses the entire day, and when too frequently followed is apt to render one coarse. Make use of the third when you feel inclined, maintaining a small breeding stud, for which your country is admirably adapted, with about thirty fine horses always at your disposal. I warn you, however, not to over-exert yourself in this or similar exercise, for excessive fatigue brings on many infirmities, as has happened to myself. Fencing is likewise most needful, especially that called wide fighting, for close-quarters are dangerous, and of little real avail. Instrumental music and singing are excellent recreations, as well as dancing to give the body freedom. Swimming is also an excellent preservative, especially in travelling. "Do not indulge too much in sleeping. Eat and drink of everything indifferently, without reference to diet such as is recommended by physicians, of whom keep aloof while you can, never calling them in until you are ill; but when really so, obey them strictly, committing yourself first to God, and secondly to their skill. "Remember, as soon as convenient, to complete your marriage with the sister of the Grand Duke of Tuscany; for no alliance could be found better or more entirely suitable for this state, for our house, or for yourself. To her, as your wife, be ever most affectionate; yet see that she meddle not in the affairs of government, but more particularly that she does not interfere in matters regarding the administration of justice. Endeavour always to maintain a most friendly footing with her family, paying to the Grand Duke the deference due to a father, and consulting him on every incident of importance.