In the times when the Tevinter Imperium empire extended into Fereldan Valley, the Tevinter magisters once engaged in a vicious battle with the Clayne. Only with the use of blood magic and a magical suit of armour were the Tevinters able to claim any victories. However, in-fighting caused a number of their leaders to die. This gave the Clayne the advantage, and Tevinter outposts fell to the barbarians.
They are also described by Master Ilen during the Dalish Elf Origin. The Sabrae clan (including Ilen's father) fought the Clayne as the Dalish fled the Dales to enter into Ferelden. The elves inflicted many causalities on the Clayne in this battle.