Cohors IV Delmatarum

Cohors IV Delmatarum
Roman infantry helmet (late 1st century)
Active	early 1st century to at least early 2nd century
Country	Roman Empire
Type	Roman auxiliary cohort
Role	infantry
Size	480 men
Garrison/HQ	Britannia 103-126

Cohors quarta Delmatarum ("4th Cohort of Dalmatae") was a Roman auxiliary infantry regiment raised in the 1st century AD and continuing to serve into the 2nd century.

The cohort is named after the Dalmatae, an Illyrian-speaking tribe that inhabited the Adriatic coastal mountain range of the eponymous Dalmatia. The ancient geographer Strabo describes these mountains as extremely rugged, and the Dalmatae as backward and warlike. He claims that they did not use money long after their neighbours adopted it and that they "made war on the Romans for a long time". He also criticises the Dalmatae, a nation of pastoralists, for turning fertile plains into sheep pasture.^[1] Indeed, the name of the tribe itself is believed to mean "shepherds", derived from the Illyrian word delme ("sheep").^[2] The final time this people fought against Rome was in the Illyrian revolt of 6-9 AD. The revolt was started by Dalmatae auxiliary forces and soon spread all over Dalmatia and Pannonia. The resulting war was described by the Roman writer Suetonius as the most difficult faced by Rome since the Punic Wars two centuries earlier. But after the war, the Dalmatae became a loyal and important source of recruits for the Roman army.

According to Holder, a total of 12 cohortes Delmatarum appear to have been raised after the suppression of the Illyrian revolt in two series, of 7 and 5 respectively. All these units were in existence by the time of emperor Claudius (r. 41-54)^[3] Of these, 9 appear to have survived into the 2nd century.^[4]

The regiment was probably raised by founder-emperor Augustus (r. 30BC-14AD) after 9 AD. It was certainly in existence by the time of Claudius (r. 41-54).^[3] Its early movements are unknown. Holder suggests that the regiment may have taken part in the Roman invasion of Britain (43) or the suppression of the revolt of Boudicca in 61.^[5] But this ignores the evidence of three 1st-century tombstones from the Rhine forts of Bingen and Bingerbrück in Germania, where it was clearly stationed. The regiment first appears in the datable epigraphic record in 103, in Britannia. It was still there in 126-30, the time of its last datable inscription, a building inscription at the Roman fort of Hardknott (Cumbria). The latter is incomplete, but is plausibly though not conclusively attributed to IV Delmatarum. The regiment's disappearance from the epigraphic record in the early 2nd century has led Spaul to suggest that the regiment was merged with another to form the cohors I Pannoniorum et Delmatarum equitata c.R. attested in Germania Inferior in 127 and beyond.^[6] But the record overall is too incomplete to support any firm conclusions.

The names of three praefecti (regimental commanders) are attested.^[7] Titus Iunius Severus was a Spaniard from Denia. A second man, whose middle name only, Pactumerius, has survived, left a votive stone at Madaura in Numidia (Mdaurusch, Algeria). The origin of the third, Lucius Aprius Liburnus, is revealed by his cognomen (third name): of the Liburni tribe, western neighbors of the Dalmatae. In addition, the names of three caligati (common soldiers) survive on the 1st-century tombstones from Bingen. All were Illyrians: one Dalmata, one Liburnus and one Daverzus.

• List of Roman auxiliary regiments

• Holder, Paul Studies in the Auxilia of the Roman Army (1980)
• Holder, Paul The Roman Army in Britain (1982)
• Spaul, John COHORS 2 (2000)