Among the many documents on papyri recovered through excavation at Dura Europos (mod. Salihye) are those from the files of the Cohors Vicesima Palmyrenorum. It was formed probably from a contingent of Palmyrene archers who were known to be in the city in 170/1 and the oldest document which names the cohors is dated to AD 208. The unit was the main garrison of Dura until the fall of the city to the Persians in 256. It was a cohors miliaria divided with a maximum of six centuries of infantry, augmented by cavalry and dromedarii. The following three texts are chosen because of their uniqueness, their relatively good state of preservation and the fact that they fall chronologically into the period covered by this collection.
(For translation of military terms, see Glossary, pp. 401-402. )
Unit journals had been in existence for the Roman Army since the Late Republic and the specimens from Dura are among the fullest preserved anywhere. Besides giving the total of the available manpower with separate statements of their NCOs for the infantry, the dromedarii and the cavalry, they also include such material of interest as the name(s) of the tribune, the full title of the unit (which changes with each new emperor) and departures and returns of detachments or individuals on specific tasks. For full discussion, see Fink, 1971:179-82.