Osmanlı Devleti’nin kurucusu Osman Gazi’nin oğlu olan Orhan’ın doğum tarihi tartışmalıdır. 699’da (1299) Nilüfer’le evlendiğinde “yiğit” (genç) diye anılmış olmasından hareketle bu tarihte on sekiz yaş civarında olduğu düşünülebilir. Osmanlı rivayetine göre, tutsak edilen Yarhisar tekfurunun (tekvur) kızı Nilüfer’le (Lülüfer, Rumca Luludia/çiçek) evlendirilmiş, Süleyman ve Murad bu evlilikten doğmuştur.

The author believes that this article offers a detailed historical account of Orhan's time (1324-1362). Here, the primary sources, mainly Ottoman and Byzantine chronicles and docments, are critically analyzed and re-examined through toponymical and topographical scholarly field word, thus reaching a reliable picture of the period of the foundation of the period of the foundation of the Ottoman hegemony in Anatolia and Rumili. The epoch-making event of the Ottoman seetlement in Thrace ( 1352-1361 ),together with the conquest of Adrianople (Edirne in 1361), is re-examined using reliable evidence from the Düsturname and the Genoese sources. Also, the significance of the first crusade against the Ottomans at Lapseki (Lampaskos) on the Dardanelles (!359) and the reorganization of the Ottoman beylik under the first vizirs of Ulema origin is emphasized. The political and cultural impact of immigration from inner Anatolia towards the frontier (Ucat), including that of the ahis and babais, along with the establishment of a bureaucracy in the period is noted. The author believes this study may be considered the most comprehensive and reliable account of Orhan's reign (1324-1362).