"This view has been objected to by other historians however, and more recent scholarship dates their creation later, to the period from the 640s to the 660s, under Constans II (r. 641–668).It has further been shown that, contrary to Ostrogorsky's conception of the being established from the outset as distinct, well-defined regions where a held joint military and civil authority, the term originally seems to have referred exclusively to the armies themselves, and only in the later 7th or early 8th centuries did it come to be transferred to the districts where these armies were encamped as well.