The earliest datable reference to Saracens is found in Ptolemy’s Geography (2nd century), which describes Sarakene as a region in the Northern Sinai named after the town Saraka located between Egypt and Palestine. There are references to that area containing Saracens, Taeni, and Arabes in that area, all separate peoples. The Notitia dignitatum, dating from the time of Diocletian, during the 3rd century, distinguishes between Arabs, Iiluturaens and Saracensas, comprising distinctive units within the Roman army.