Alexander did as citizen Morgan is doing; only, instead of stopping the coaches on the highroads, he pillaged cities, held kings for ransom, levied contributions from the conquered countries.

Let us turn to Hannibal.

You know how he left Carthage, don't you?
He did not have even the eighteen or twenty talents of his predecessor; and as he needed money, he seized and sacked the city of Saguntum in the midst of peace, in defiance of the fealty of treaties.

After that he was rich and could begin his campaign.

Forgive me if this time I no longer quote Plutarch, but Cornelius Nepos.