Although it is little known, Medieval Muslim historians mentioned the history of the Roman Empire in their works. Of these Târîhu’l-Ya‘kūbî (d. 292/905), respected one of the leading historians and geographers of the Medieval Muslim school, in his work Târîhu’l-Ya‘kūbî, provides the reader with basic information and this work contains the oldest Muslim historical records concerning the Roman Empire which has survived to date amongst the Medieval Muslim written sources. It seems most probable that the source of this information was Claudius Ptolemaios (II. century A.D.), from his Πρόχειροι ϰανόνες (Tabulae manuales). However, the text that Ya'kūbî employs in his work is no simple transcription of Ptolemaios’ work but was updated and modified with additions from Theon Alexandrinus (. IV.-V. c. A.D.). The record provided by Târîhu’l-Ya‘kūbî is not full of detail but was content to convey some information in a summarised form and, for this reason, it is more accurate to describe it as a “List of Roman Emperor’s”. Despite having a very good understanding of the Eastern Roman Empire which they bordered and were constantly in contact with in various ways, the Muslims’ knowlege of the history of the Roman Empire must have been through this list, a point of importance when evaluated from this point of view.