Read the passage from chapter 17 of The Prince. And of all princes, it is impossible for the new prince to avoid the imputation of cruelty, owing to new states being full of dangers. Hence Virgil, through the mouth of Dido, excuses the inhumanity of her reign owing to its being new, saying:

"Res dura, et regni novitas me talia cogunt
Moliri, et late fines custode tueri."(*)

Nevertheless he ought to be slow to believe and to act, nor should he himself show fear, but proceed in a temperate manner with prudence and humanity, so that too much confidence may not make him incautious and too much distrust render him intolerable.

. . . against my will, my fate
A throne unsettled, and an infant state,
Bid me defend my realms with all my pow'rs,
And guard with these severities my shores.

Which type of evidence does Machiavelli use in the story of Dido to show that a ruler should be cruel in certain circumstances?