Ptolemy's 2nd-century work, Geography, describes Sarakēnḗ () as a region in the northern Sinai Peninsula. Ptolemy also mentions a people called the Sarakēnoí () living in the northwestern Arabian Peninsula (near neighbor to the Sinai). Eusebius in his Ecclesiastical history narrates an account wherein Pope Dionysius of Alexandria mentions Saracens in a letter while describing the persecution of Christians by the Roman emperor Decius: Many were, in the Arabian mountain, enslaved by the barbarous 'sarkenoi'. The Augustan History also refers to an attack by Saraceni on Pescennius Niger's army in Egypt in 193, but provides little information as to identifying them.