Money is not the Sinew of War although this is common opinion

Because anyone can commence a war at his pleasure, but cannot so finish it, a Prince ought before he undertakes an enterprise to measure his forces, and govern himself in accordance with them. But he ought to have so much prudence as not to deceive himself of the two forces: and he will deceive himself every time when he measures it either by his money, or by the location [of his country], or by good will of his people, while on the other hand he lacks his own arms. For although the above things will increase his strength, [but] they will not give it to him, and of themselves are nothing, and will not be of benefit without trustworthy arms. For without them, great amounts of money will not suffice you, the strength of the country will not benefit you, and the faith and good will of men will not endure, as these cannot remain faithful to you if you are not able to defend them. Every mountain, every lake, every inaccessible place becomes a plain where strong defenders are lacking. Money alone, also, will not defend you, but causes you to be plundered more readily. Nor can that common opinion be more false which says that money is the sinew of war. Which sentence was said by Quintus Curtius in the war which existed between Antipater the Macedonian and the King of Sparta, where he narrates that because of a want of money the King of Sparta was obliged to come to battle and was routed, that if he had deferred the fight a few days the news of the death of Alexander in Greece would have arrived, whence he would have remained victor without fighting. But lacking money, and being apprehensive that, for the want of which, his army would abandon him, was constrained to try the fortune of battle. So that for this reason Quintus Curtius affirms money to be the sinew of war. Which opinion is alleged every day, and acted on by not so prudent Princes to whom it is enough to follow it: For relying on it, they believe it is enough to have much treasure to defend themselves, and do not think that if treasure should be enough to win, that Darius would have vanquished Alexander, the Greeks would have vanquished the Romans, and in our times Duke Charles would have vanquished the Swiss, and a few days ago the Pope and the Florentine together would not have had difficulty in defeating Francesco Maria, nephew of Julius II, in the war at Urbino. But all the above named were vanquished by those who esteemed not money, but good soldiers, as the sinew of war.

Among other things that Croesus, King of Lydia, showed to Solon the Athenian was a countless treasure: and asking what he thought his power to be, Solon answered that he did not judge him more powerful because of that, because war was made with iron and not gold, and that someone might come who had more iron than he and would take it away from him. In addition to this, when, after the death of Alexander the Great, a great multitude of Gauls passed into Greece and then into Asia, and the Gauls sent Ambassadors to the King of Macedonia to treat of certain accords, that King to show his power and to dismay them showed them much gold and silver: whence those Gauls who had already as good as signed the peace broke it, so much did the desire grow in them to take away that gold. And thus was that King despoiled by the very thing that he had accumulated for defense. The Venetians a few years ago also, having their Treasury full of treasure, lost the State............