What is "damnonii"

The Damnonii (also referred to as Damnii) were a people of the late 2nd century who lived in what became the Kingdom of Strathclyde by the Early Middle Ages, and is now southern Scotland. They are mentioned briefly in Ptolemy's Geography, where he uses both of the terms "Damnonii" and "Damnii" to describe them, and there is no other historical record of them, except arguably by Gildas three centuries later. Their cultural and linguistic affinity is presumed to be Brythonic. However, there is no unbroken historical record, and a partly Pictish origin is not precluded.

The Romans under Agricola had campaigned in the area in 81, and it was Roman-occupied (at least nominally) between the time that Hadrian's Wall was built (c. 122), through the building of the Antonine Wall (c. 138), until the pullback to Hadrian's Wall in 164. Ptolemy's Geography was written within this timeframe, so his account is contemporary.