Nilüfer Hatun, a concubine of Orhan, the second Ottoman sultan, stands at the hazy but momentous threshold of early Ottoman history — a period where fact and legend blend as readily as the frontier cultures from which the young beylik emerged. As the mother of Murad I, the sultan who would transform the Ottomans from a border principality into an ascendant power, Nilüfer occupies one of the earliest and most consequential positions in the dynasty's lineage. However, she also represents one of its greatest historiographical puzzles.