The Prince by Niccolo Machiavelli Chapter 4 Page 6

defeat him utterly and strip him of his dominions; after which defeat, Darius having died, the country, for the causes above explained, was permanently secured to Alexander. And had his successors continued united they might have enjoyed it undisturbed, since there arose no disorders in that kingdom save those of their own creating.

But kingdoms ordered like that of France cannot be retained with the same ease. Hence the repeated risings of Spain, Gaul, and Greece against the Romans, resulting from the number of small Princedoms of which these Provinces were made up. For while the memory of these lasted, the Romans could never think their tenure safe. But when that memory was worn out by the authority and long continuance of their rule, they gained a secure hold, and were able afterwards in their contests among themselves,