 The emirs could not usurp the throne themselves, however, and had Caliph al-Musta'in installed; the caliph had the support of the non-Circassian mamluks and legitimacy with the local population.Six months later, Shakyh eased al-Musta'in out of power after neutralizing his main rival, Nawruz, and assumed the sultanate.Shaykh's main goal in office was restoration of the state's authority within the sultanate, which saw further plagues in 1415–1417 and 1420.