“May I offer you the advice of the 14th century Arab historian Ibn Khaldun, who said: 'At the beginning of the empire, the tax rates were low and the revenues were high. At the end of the empire, the tax rates were high and the revenues were low.'

And, no, I did not personally know Ibn Khaldun, although we may have had some friends in common!”

- Ronald Reagan, who cited Ibn Khaldun's economic theories during his presidency