Diversified policies toward other religions and cultures, military might, and concentration of the resources of the best part of the Mediterranean allowed the sultans to create a vast empire. In a sense, they could even consider themselves heirs to the Byzantine emperors, spared their shortcomings. I've just returned from Turkish Antalya, where the city's police coat of arms still features a Byzantine double-headed eagle and a founding date. Tradition is what sustained Ottoman power (and continues to sustain the ambitions of the modern Turkish Republic).