Many explanatory suppositions have been off ered to account for the civil disorder that struck so many Arab countries in the first six months of 2011. The popular term for this multi-nation upheaval is the Arab Spring. Most of these theories, however, have lacked a mechanism for linking the challenges to existing governments to the specific Arab societies that experienced them. The approach that will be advanced here is that the Arab Spring represented a failure of legitimacy on the part of a particular political formation —rule by military officers and their families, which bore the brunt of the popular uprisings of the Arab Spring. Why did the legitimacy of this system of rule suffer simultaneous collapse while other Arab regimes, in particular the monarchies, did not? I term this political formation neo-Mamluk rule to connect it to precursor regimes that go back to the twelfth and thirteenth centuries. Only by tracing the origins of neo-Mamluk rule can one discover the keys to the crisis of legitimacy that has been manifest in recent months.