[6][better source needed][1] The 1324 endowment deed for a Dervish Monastery built by Sultan Orhan suggests that his mother was not, as popular historical tradition maintains, Edebali's daughter but rather Mal Hatun, the daughter of one "Umar Bey or Ömer Bey".

The title "Bey", used by the princely dynasties of Anatolia, suggests that Mal Hatun's father was a person of some status and authority.

One possibility is that he was the eponymous ruler of an "Amouri" (Umeri) Principality, which was located northeast of the emerging Ottoman State and disappeared in the late 13th or the early 14th century.

The Ottomans, according to Pachymeres, went on to assume the role played by Amouri until their demise as the principal aggressor against the Byzantines in the northwest Anatolia.

If Pachymeres's report is correct, the timing and the political context are appropriate for a marriage between Osman and Umar Bey's daughter.