This article in the Economist says: "Ottoman sultans solved this problem by murdering their brothers. " This reminded me, in the account in Soliman le magnifique et son temps. Paris 1992, pp. 117-124 it says: "Mehmed II codified an older custom whereby it was considered permissible for a reigning sultan to eliminate his brothers soon after taking the throne. In his kanunname, Melmed II decreed that: "For the welfare of the state, the one of my sons to whom God grants the sultanate may lawfully put his brothers to death. A majority of the 'ulema consider this permissible." ( The translation provided by Franz Babinger is somewhat different: "Whichever of my sons inherits the sultan's throne, it behooves him to kill his brothers in the interest of the world order. Most of the jurists have approved this procedure. Let action be taken accordingly." In fact, this practice was interpreted to include the execution not only of brothers, but also nephews and uncles." As for the case of Iran under the Safavids, "Shah Abbas I the Great" (r. 1587-1629) who is considered the most just and greatest of the rulers, killed one of his sons and blinded two others to disqualify them from ruleship.