He has only to take care that they do not get hold of too much power and too much authority, and then with his own forces, and with their goodwill, he can easily keep down the more powerful of them, so as to remain entirely master in the country.

And he who does not properly manage this business will soon lose what he has acquired, and whilst he does hold it he will have endless difficulties and troubles.
The Romans, in the countries which they annexed, observed closely these measures; they sent colonies and maintained friendly relations with( *) the minor powers, without increasing their strength; they kept down the greater, and did not allow any strong foreign powers to gain authority.
Greece appears to me sufficient for an example.

The Achaeans and Aetolians were kept friendly by them, the kingdom of Macedonia was humbled, Antiochus was driven out; yet the merits of the Achaeans and Aetolians never secured for them permission to increase their power, nor did the persuasions of Philip ever induce the Romans to be his friends without first humbling him, nor did the influence of Antiochus make them agree that he should retain any lordship over the country.

Because the Romans did in these instances what all prudent princes ought to do, who have to regard not only present troubles, but also future ones, for which they must prepare with every energy, because, when foreseen, it is easy to remedy them; but if you wait until they approach, the medicine is no longer in time because the malady has become incurable; for it happens in this, as the physicians say it happens in hectic fever, that in the beginning of the malady it is easy to cure but difficult to detect, but in the course of time, not having been either detected or treated in the beginning, it becomes easy to detect but difficult to cure.

This it happens in affairs of state, for when the evils that arise have been foreseen (which it is only given to a wise man to see), they can be quickly redressed, but when, through not having been foreseen, they have been permitted to grow in a way that every one can see them, there is no longer a remedy.