Dell'arte della guerra (The Art of War) influenced Il principe (The Prince)

The Art of War is the only one of Machiavelli's major political books published in his lifetime, and it argues the case The Prince assumes: that a state which relies on mercenaries is defenceless, and that a citizen militia is the only reliable foundation of power. The Prince states the conclusion as a rule for a ruler; the earlier book is where it is worked out, drawing on Roman practice and on Machiavelli's own attempt to raise a Florentine militia. The relationship runs the other way from the publication dates, which is why the claim rests on the composition order rather than on the printing.