Machiavelli "The Prince" Chapter XIII
In W. Marriott's translation, there's a clause (in bold) neither the structure nor the meaning of which I'm sure:
I shall never hesitate to cite Cesare Borgia and his actions. This duke entered the Romagna with auxiliaries, taking there only French soldiers, and with them he captured Imola and Forli; but afterwards, such forces not appearing to him reliable, he turned to mercenaries, discerning less danger in them, and enlisted the Orsini and Vitelli; whom presently, on handling and finding them doubtful, unfaithful, and dangerous, he destroyed and turned to his own men. And the difference between one and the other of these forces can easily be seen when one considers the difference there was in the reputation of the duke, when he had the French, when he had the Orsini and Vitelli, and when he relied on his own soldiers, on whose fidelity he could always count and found it ever increasing; he was never esteemed more highly than when every one saw that he was complete master of his own forces.
I guess "it" is referring to the soldiers' fidelity.
J. Bennett also says it is the fidelity that was increasing:
I never hesitate to cite Cesare Borgia and his actions. This duke entered Romagna with auxiliaries—the only soldiers he had were French—and with them he captured Imola and Forlì; but he came to think that these forces weren’t reliable, so he turned to the Orsini and Vitelli troops, mercenaries, thinking them to be safer; but they turned out to be dangerous also, unreliable in battle and disloyal; so he got rid of them—·disbanding the troops and killing their leaders·—and turned to his own men. The difference between a home-grown army and those others can easily be seen in what happened to the duke’s reputation as he moved from •the French to •the Orsini and Vitelli, and from them to •relying on his own soldiers, whose loyalty to him increased as time went on. He was never esteemed more highly than when everyone saw that he was complete master of his own army.
However, other three translations all say it is Duke Cesare Borgia's reputation that was increasing:
I shall never hesitate to cite the example of Cesare Borgia and his actions. He entered Romagna with a force of auxiliaries, all of them French men-at-arms, with whom he took Imola and Forli. But it appearing to him afterwards that these troops were not to be trusted, he had recourse to mercenaries from whom he thought there would be less danger, and took the Orsini and Vitelli into his pay. But finding these likewise while under his command to be fickle, false, and treacherous, he got rid of them, and fell back on troops of his own raising. And we may readily discern the difference between these various kinds of arms, by observing the different degrees of reputation in which the Duke stood while he depended upon the French alone, when he took the Orsini and Vitelli into his pay, and when he fell back on his own troops and his own resources; for we find his reputation always increasing, and that he was never so well thought of as when every one perceived him to be sole master of his own forces.
I shall never hesitate to cite Cesare Borgia and his actions. This duke came into Romagna with auxiliary arms,leading there entirely French troops, with whom he took Imola and Forli. But when such arms no longer appeared safe to him, he turned to mercenaries, judging there to be less danger in them; and he hired the Orsini and Vitelli. Then in managing them, he found them doubtful, unfaithful, and dangerous; he eliminated them,and turned to his own arms. And one can easily see the difference between these arms if one considers what a difference there was in the reputation of the duke when he had only the French, and when he had the Orsini and Vitelli, and when he was left with his own soldiers and himself over them: his reputation will be found always to have increased,but he was never so much esteemed as when everyone saw that he was the total owner of his arms.