refers to an attack by Saraceni on Pescennius Niger's army in Egypt in 193, but provides little information as to identifying them. Both Hippolytus of Rome and Uranius mention three distinct peoples in Arabia during the first half of the third century: the Taeni, the Saraceni, and the Arabes. The Taeni, later identified with the Arab people called Tayy, were located around Khaybar (an oasis north of Medina) and also in an area stretching up to the Euphrates. The Saraceni were placed north of them. These Saracens, located in the northern Hejaz, were described as people with a certain military ability who were opponents of the Roman Empire and who were classified by the Romans as barbarians. The Saracens are described as forming the equites from Phoenicia and Thamud. In one document, the defeated enemies of Diocletian's campaign in the Syrian Desert are described as Saracens. Other 4th-century military reports make no mention of Arabs, but refer to Saracen groups ranging as far east as Mesopotamia who were involved in battles on both the Sasanian and Roman sides. The Saracens were named in the Roman administrative document Notitia Dignitatum, dating from the time of Theodosius I in the 4th century, as comprising distinctive units in the Roman army. They were distinguished in the document from Arabs. Medieval usage of the term saracene No later than the early fifth century, Jewish and Christian writers began to equate Saracens with Arabs. Saracens were associated with Ishmaelites (descendants of Abraham's older son Ishmael) in some strands of Jewish, Christian, and Islamic genealogical thinking. The writings of Jerome (d. 420) are the earliest known version of the claim that Ishmaelites chose to be called Saracens in order to identify with Abraham's "free" wife Sarah, rather than as Hagarenes, which would have highlighted their association with Abraham's "slave woman" Hagar. This claim was popular during the Middle Ages, but derives more from Paul's allegory in the New Testament letter to the Galatians than from historical data. The name Saracen was not indigenous among the populations so described but was applied to them by Greco-Roman historians based on Greek place names. As the Middle Ages progressed, usage of the term in the Latin West changed, but its connotation remained associated with opponents of Christianity, and its exact definition is unclear. In an 8th-century polemical work, John of Damascus criticized the Saracens as followers of a false