thumb|left|19th-century depiction of Osman, by Konstantin Kapıdağlı In terms of proportions, the most popular and classic narration is that Osman is the grandson of Süleyman Şah, who died drowning while crossing the Euphrates River on horseback. The Turkish historian Yılmaz Öztuna considers that Osman's grandfather, and Ertuğrul's father, is called Gündüz Alp, saying that it is more likely that Süleyman Şah is a name stuck in Anatolian popular memory, and it actually refers to Süleyman bin Qutulmish who founded the Seljuk Sultanate of Rûm. Öztuna adds that it is possible that Ottoman historians tried forming a connection between the Ottomans and the Seljuks, especially since the Ottomans appeared on the stage of history claiming to be the legitimate successors of the Seljuks. Based on this, Osman's assumed lineage is as follows: Osman bin Ertuğrul bin Gündüz Alp bin Kaya Alp bin Gökalp bin Sarquk Alp bin Kayı Alp. Other researchers agree that the connection between Ertuğrul, Osman, and the Seljuks may have been largely invented by court chroniclers a century later, and the true origins of the Ottomans thus remain obscure. On the other hand, some Ottoman sources indicate further lineage to Osman and the Oghuz Turks, which is closer to myth than reality, saying that these people are descendants of Japheth, son of Noah, and that Osman's genealogical tree contains 52 ancestors or more and ends with the Prophet Noah himself. This lineage includes Gökalp and Oghuz Han (who is said to be the father of Gökalp), and all the Oghuz Turkic peoples, including the Seljuks.
thumb|left|19th-century depiction of Osman, by Konstantin Kapıdağlı In terms of proportions, the most popular and classic narration is that Osman is the grandson of Süleyman Şah, who died drowning while crossing the Euphrates River on horseback. The Turkish historian Yılmaz Öztuna considers that Osman's grandfather, and Ertuğrul's father, is called Gündüz Alp, saying that it is more likely that Süleyman Şah is a name stuck in Anatolian popular memory and it actually refers to Süleyman bin Qutulmish who founded the Seljuk Sultanate of Rûm. Öztuna adds that it is possible that Ottoman historians tried forming a connection between the Ottomans and the Seljuks, especially since the Ottomans appeared on the stage of history claiming to be the legitimate successors of the Seljuks. Based on this, Osman's assumed lineage is as follows: Osman bin Ertuğrul bin Gündüz Alp bin Kaya Alp bin Gökalp bin Sarquk Alp bin Kayı Alp. Other researchers agree that the connection between Ertuğrul, Osman, and the Seljuks may have been largely invented by court chroniclers a century later, and the true origins of the Ottomans thus remain obscure. On the other hand, some Ottoman sources indicate further lineage to Osman and the Oghuz Turks, which is closer to myth than reality, saying that these people are descendants of Japheth, son of Noah, and that Osman's genealogical tree contains 52 ancestors or more and ends with the Prophet Noah himself. This lineage includes Gökalp and Oghuz Han (who is said to be the father of Gökalp), and all the Oghuz Turkic peoples, including the Seljuks.