In Chapter 3 of the Prince Machiavelli offers this advice to the prince who would hold a newly acquired territory:
[T]o send colonies to one or two places, which may be as keys to that state, for it necessary either to do this or else to keep there a great number of cavalry and infantry. A prince does not spend much on colonies, for with little or no expense he can send them out and keep them there, and he offends a minority only of the citizens from whom he takes lands and houses to give them to the new inhabitants; and those whom he offends, remaining poor and scattered, are never able to injure him; whilst the rest being uninjured are easily kept quiet, and at the same time are anxious not to err for fear it should happen to them as it has to those who have been despoiled.
Unless I am very much mistaken, he has his favourite ancient Romans in mind and their method of holding and policing territory by veterans' colonies.
However, I do not recall any instances of medieval or Renaissance colonies of this kind which Machiavelli might have had in mind. Indeed, he gives no illustration of his colonies advice, while he copiously illustrates other advice with contemporary examples.
So I wonder if I missed some cases - or perhaps Machiavelli was being here more of bit of an antiquarian? (like he is a lot of times in his Art of War)
P.S. My wife suggested one great example - the Ulster Plantation. But probably Machiavelli was not sufficiently clairvoyant to know about it.