Ertuğrul was the father of Osman I, the founder of the Ottoman Empire. He was the ruler of the Kayı tribe, which was located around the southeast coast of Marmara. [noted -ed]
Ertuğrul Osman (1912-2009) was an Ottoman prince. He was one of the last members of the Ottoman imperial family born during the empire's existence and was head of the Ottoman imperial family from 1994 until his death.