Niccolò Machiavelli
Discourses on the First Decade of Titus Livius (Chap. 3.3)
That to preserve a newly acquired Freedom we must slay the Sons of Brutus.

The severity used by Brutus in preserving for Rome the freedom he had won for her, was not less necessary than useful. The spectacle of a father sitting on the judgment, and not merely sentencing his own sons to death, but being himself present at their execution, affords an example rare in history. But those who study the records of ancient times will understand, that after a change in the form of a government, whether it be from a commonwealth to a tyranny or from a tyranny to a commonwealth, those who are hostile to the new order of things must always be visited with signal punishment. So that he who sets up as a tyrant and slays not Brutus, and he who creates a free government and slays not the sons of Brutus, can never maintain himself long. But since I have elsewhere treated of this matter at large, I shall merely refer to what has there been said concerning it, and shall cite here one instance only, happening in our own days, and memorable in the history of our country.

I speak of Piero Soderini, who thought by his patience and goodness to overcome the very same temper which prompted the sons of Brutus to revert to the old government, and who failed in the endeavour. For although his sagacity should have taught him the necessity, while chance and the ambition of those who attacked him furnished him with the opportunity of making an end of them, he never could resolve to strike the blow; and not merely believed himself able to subdue disaffection by patience and kindness, and to mitigate the enmity of particular men by the rewards he held out to them, but also persuaded himself, and often declared in the presence of his friends, that he could not confront opposition openly, nor crush his adversaries, without assuming extraordinary powers and passing laws destructive of civil equality; which measures, although not afterward used by him for tyrannical ends, would so alarm the community, that after his death they would never again consent to appoint a Gonfalonier for life, an office which he judged it essential both to maintain and strengthen. Now although these scruples of his were wise and good, we ought never out of regard for what is good, to suffer an evil to run its course, since it may well happen that the evil will prevail over the good. And Piero should have believed that as his acts and intentions were to be judged by results, he might, if he lived and if fortune befriended him, have made it clear to all, that what he did was done to preserve his country, and not from personal ambition; and he might have so contrived matters that no successor of his could ever turn to bad ends the means which he had used for good ends. But he was misled by a preconceived opinion, and failed to understand that ill-will is not to be vanquished by time nor propitiated by favours. And, so, from not knowing how to resemble Brutus, he lost power, and fame, and was driven an exile from his country.

That it is as hard a matter to preserve a princedom as it is to preserve a commonwealth, will be shown in the Chapter following.