It is named after the Dalmatae, an Illyrian-speaking tribe that inhabited the Adriatic coastal mountain range of the eponymous Dalmatia.

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.

[2] The Notitia Dignitatum, a late Roman official document, records a cohors II Delmatarum at Magnis under the dux Britanniarum, the commander of limitanei (border forces) along Hadrian's Wall.

[5] The Western section of the Notitia was drawn up in the 420s, but the British units must date to before 410, when the island was evacuated by the Roman army.

Also attested is an imaginifer (bearer of the imperial image) (3rd century) and a pedes (common foot soldier) of the Treveri Gallic tribe (135).