Saint Augustine on pirates

Having discussed pirates here, I was interested to find this quote on Marginal Revolution

In the "City of God," St. Augustine tells the story of a pirate captured by Alexander the Great. The Emperor angrily demanded of him, "How dare you molest the seas?" To which the pirate replied, "How dare you molest the whole world? Because I do it with a small boat, I am called a pirate and a thief. You, with a great navy, molest the world and are called an emperor." St. Augustine thought the pirate's answer was "elegant and excellent."