Name of the Imeriata
Historically so have the land of Imeriata been called a lot and for instance so have "Imerrike", "Imermark" and "Imerland" also been used and it takes it name from Imer the great. The hero that conquered what today is Imeriata proper from the Wharen. The term Imeriata itself (as were Imerrike) however were often used to describe the realm that Imer ruled and was the idea of a pan-Imerian kingdom while the land itself were often referred to as Imermark and Imerland and when Emanuel the first proclaimed himself high king so did he name himself high king of Imeriata which made the name official and the term "Imerrike" fell out of use shortly thereafter.
Imermark and Imerland however were still in use but were in time replaced with the term "Imeriata proper" even if there have been several serious attempts to change that to Imermark and Imerland.