This text deals with the process of decline of the Mameluk state (1250-1517). Its main thesis is that the origins of this process are to be found in the third reign of al-Nasir Muhammad Ibn Qalawun, and more specifically in the changes he effected in the Mameluk system. The Mameluk army was the first to be confronted with these changes, whose impact on the social and political life of the Mameluk elite was already felt during al-Nasir's lifetime. This text follows the developments to the end of autonomous Mameluk rule and reveals the transformation they wrought in the Mameluk code of values and political concepts. A final chapter deals with the overall economic decline of the Mameluk state and establishes the link of its various causes - demographic decline, monetary crises, the collapse of agriculture and industry - with Mameluk government misrule. The conclusion is reached that it was al-Nasir's expenditure policy and its repercussions on the economic reform which reveal his reign as a point of no return.