The King of Arthedain was a title created after the breakup of Arnor into the sub-kingdoms of Arthedain, Cardolan, and Rhudaur in TA 861. After the death of Eärendur, his three sons quarreled over the succession causing a civil war between them and their respective realms. Amlaith, the eldest son claimed the throne of Arnor but his rule was limited only to the region of Arthedain with its capital in Annúminas near Lake Evendim and then Fornost, while the others founded Cardolan and Rhudaur.