(Meant to have something of my own, but I’ve fallen down with a bad cold and don’t have much in the way of thinking powers. So enjoy the advice of St. Louis IX to his son)

1. To his dear first-born son, Philip, greeting, and his father’s love.

2. Dear son, since I desire with all my heart that you be well “instructed in all things, it is
in my thought to give you some advice this writing. For I have heard you say, several
times, that you remember my words better than those of any one else.

3. Therefore, dear son, the first thing I advise is that you fix your whole heart upon God,
and love Him with all your strength, for without this no one can be saved or be of any
worth.

4. You should, with all your strength, shun everything which you believe to be displeasing to Him. And you ought especially to be resolved not to commit mortal sin, no matter what may happen and should permit all your limbs to be hewn off, and suffer every manner of torment , rather than fall knowingly into mortal sin.

5. If our Lord send you any adversity, whether illness or other in good patience, and thank Him for it, thing, you should receive it in good patience and be thankful for it, for you ought to believe that He will cause everything to turn out for your good; and likewise you should think that you have well merited it, and more also, should He will it, because you have loved Him but little, and served Him but little, and have done many things contrary to His will.

6. If our Lord send you any prosperity, either health of body or other thing you ought to thank Him humbly for it, and you ought to be careful that you are not the worse for it, either through pride or anything else, for it is a very great sin to fight against our Lord with His gifts.

7. Dear son, I advise you that you accustom yourself to frequent confession, and that you choose always, as your confessors, men who are upright and sufficiently learned, and who can teach you what you should do and what you should avoid. You should so carry yourself that your confessors and other friends may dare confidently to reprove you and show you your faults.

8. Dear son, I advise you that you listen willingly and devoutly the services of Holy Church, and, when you are in church, avoid to frivolity and trifling, and do not look here and there; but pray to God with lips and heart alike, while entertaining sweet thoughts about Him, and especially at the mass, when the body and blood of our Lord Jesus Christ are consecrated, and for a little time before.

9. Dear son, have a tender pitiful heart for the poor, and for all those whom you believe to be in misery of heart or body, and, according to your ability, comfort and aid them with some alms.

10. Maintain the good customs of your realm, and put down the bad ones. Do not oppress your people and do not burden them with tolls or tailles, except under very great necessity.

11. If you have any unrest of heart, of such a nature that it may be told, tell it to your confessor, or to some upright man who can keep your secret; you will be able to carry more easily the thought of your heart.

12. See to it that those of your household are upright and loyal, and remember the Scripture, which says: “Elige viros timentes Deum in quibus sit justicia et qui oderint avariciam”; that is to say, “Love those who serve God and who render strict justice and hate covetousness”; and you will profit, and will govern your kingdom well.

(The rest can be found here)