Machiavelli had 27 Rules of military discipline which were described in his book The Art of War. Upon reading the book, you may find that many of them were very similar to rules that Sun Tzu and Clausewitz popularized both before and after Machiavelli.
"I know that I have spoken to you of many things, which you have been able to understand and consider by yourselves; none the less, I have done this ((as I also told you today)) to be able to show you, through them, the better kind of training, and also to satisfy those, if there should be any, who had not had that opportunity to learn, as you have. Nor does it appear to me there is anything left for me to tell you other than some general rules, with which you should be very familiar: which are these:"
- What benefits the enemy, harms you; and what benefits you, harms the enemy.
- Whoever is more vigilant in observing the designs of the enemy in war, and endures much hardship in training his army, will incur fewer dangers, and can have greater hope for victory.
- Never lead your soldiers into an engagement unless you are assured of their courage, know they are without fear, and are organized, and never make an attempt unless you see they hope for victory.
- It is better to defeat the enemy by hunger than by steel; in such victory fortune counts more than virtu.
- No proceeding is better than that which you have concealed from the enemy until the time you have executed it.
- To know how to recognize an opportunity in war, and take it, benefits you more than anything else.
- Nature creates few men brave, industry and training makes many.
- Discipline in war counts more than fury.
- If some on the side of the enemy desert to come to your service, if they be loyal, they will always make you a great acquisition; for the forces of the adversary diminish more with the loss of those who flee, than with those who are killed, even though the name of the fugitives is suspect to the new friends, and odious to the old.
- It is better in organizing an engagement to reserve great aid behind the front line, than to spread out your soldiers to make a greater front.
- He is overcome with difficulty, who knows how to recognize his forces and those of the enemy.
- The virtu of the soldiers is worth more than a multitude, and the site is often of more benefit than virtu.
- New and speedy things frighten armies, while the customary and slow things are esteemed little by them: you will therefore make your army experienced, and learn (the strength) of a new enemy by skirmishes, before you come to an engagement with him.
- Whoever pursues a routed enemy in a disorganized manner, does nothing but become vanquished from having been a victor.
- Whoever does not make provisions necessary to live (eat), is overcome without steel.
- Whoever trusts more in cavalry than in infantry, or more in infantry than in cavalry, must settle for the location.
- If you want to see whether any spy has come into the camp during the day, have no one go to his quarters.
- Change your proceeding when you become aware that the enemy has foreseen it.
- Counsel with many on the things you ought to do, and confer with few on what you do afterwards.
- When soldiers are confined to their quarters, they are kept there by fear or punishment; then when they are led by war, (they are led) by hope and reward.
- Good Captains never come to an engagement unless necessity compels them, or the opportunity calls them.
- Act so your enemies do not know how you want to organize your army for battle, and in whatever way you organize them, arrange it so that the first line can be received by the second and by the third.
- In a battle, never use a company for some other purpose than what you have assigned it to, unless you want to cause disorder.
- Accidents are remedied with difficulty, unless you quickly take the facility of thinking.
- Men, steel, money, and bread, are the sinews of war; but of these four, the first two are more necessary, for men and steel find money and bread, but money and bread do not find men and steel.
- The unarmed rich man is the prize of the poor soldier.
- Accustom your soldiers to despise delicate living and luxurious clothing.