Despite frequently being referred to as a "system", before the nineteenth century the organization of what are now retrospectively called millets in the Ottoman Empire was not at all systematic. Rather, non-Muslims were simply given a significant degree of autonomy within their own community, without an overarching structure for the 'millet' as a whole. The notion of distinct millets corresponding to different religious communities within the empire would not emerge until the eighteenth century. Subsequently, the existence of the millet system was justified through numerous foundation myths linking it back to the time of Sultan Mehmed the Conqueror (r. 1451–81), although it is now understood that no such system existed in the fifteenth century.