Explanation: The Mamluks were the military caste of Egypt, first founded during the medieval period. Over time, they grew into a kind of pseudo-nobility more adept at coups than defending against foreign invaders. In 1811, Muhammad Ali, the Ottoman-appointed ruler of Egypt, invited them all to a nice party in honor of his son!

… and massacred the lot of them so he could get on with his modernizing reforms to make Egypt an independent power once more.