Answer:
Niccolò Machiavelli in The Prince describes the role of the three armies: mercenary, auxiliary troops and a prince’s troops.
Mercenary and auxiliary troops are considered to be dangerous because they are driven by ambition, power and money. Therefore, a prince should have his army.
So, Machiavelli advises the Prince to use internal troops made out of civilians because he could rely on it. They will fight for the kingdom and will not betray him.
