From Niccolò Machiavelli’s The Prince, Chapter Twelve:
Mercenaries and auxiliaries are both useless and dangerous. Anyone who relies on mercenary troops to keep himself in power will never be safe or secure, for they are fractious, ambitious, ill-disciplined, treacherous. They show off to your allies and run away from your enemies. They do not fear God and do not keep faith with mankind. A mercenary army puts off defeat for only so long as it postpones going into battle. In peacetime they pillage you, in wartime they let the enemy do it. This is why: They have no motive or principle for joining up beyond the desire to collect their pay. And what you pay them is not enough to make them want to die for you. They are delighted to be your soldiers when you are not at war; when you are at war, they walk away when they do not run.From the translation by David Wootton, copyright © 1995 by Hackett Publishing Company.
It is true that occasionally a ruler seems to benefit from their use, and they boast of their own prowess, but as soon as they face foreign troops their true worth becomes apparent.
Experience shows individual sovereigns and republics that arm the masses are capable of making vast conquests; but mercenary troops are always a liability.
From the ghost of radio blogging past, via the Internet Archive and the Wayback Machine, Joe Queenan gives A Brief History of Cunning, on Machiavelli and more. MP3 here.
From the archives of BBC Radio 4’s In Our Time, a 2004 episode on Machiavelli and the Italian city states.
From the pen of Don MacDonald, a biography of Machiavelli in comics, starting here. As he explains, The Prince is not a satire, and via Don’s blog, Timo Laine’s guide to Machiavelli on the net.
From the Hollywood version of Machiavelli’s Italy, Orson Welles as Cesare Borgia, the tyrant ultimately unable to conquer the people in Prince of Foxes. Tyrone Power plays the political officer who betrays his paymaster in pursuit of his own interests, in the form of Wanda Hendrix.
An earlier post on Machiavelli is here.