There is a debate on the name of Dede Qorqud among historians and linguistics. Historians believe that the name is an special name for a certain person who wrote the Bayat tribe's mythical stories. However, linguistically, dede is just a modifier for qorqud. i.e.: qorqud was a common name and just one of those people who had this name had been identified by dede. The same process works in the combinations such as Shah Ismail, Sultan Selim, or in the everyday language Kanim Solmaz. However, qorqud is not yet a common name neither in Azerbaijan nor in Turkey (the popularity of the name is a place of study in the communities that locate to the west of Caspian Lake). Today, I learned that there was an Ottoman prince with the same name: Şehzade Korkut (wiki). This may be considered as a fact on the popularity of this in the late ancient Turkish proper names.