Decline of Medieval Iraq
Throughout the period of Abbasid glory in Baghdad (750-861 [C.E.]), the priceless oriental trade from India and China to Byzantium and Europe has passed up the Persian Gulf and through Baghdad to northern Syria. But the administration of Ibn Tulun in Egypt was so just and conditions in Iraq were so chaotic, that the merchants who handled the oriental trade decided to switch their route from the Persian Gulf to the Red Sea and Egypt. This was the beginning of the rise of Egypt and the decline of Iraq.
— Soldiers of Fortune, p. 24