Modern historians have proffered two interpretations of the 10th-century use of "dux Francorum". Jan Dhondt and Walther Kienast argued that the title was a royal concession recognising the actual power acquired by the Robertians over the region known as "Francia", that is, old Neustria. Thus the title was territorial in nature, reflective of Hugh's real power and a royal (legal) grant. Ferdinand Lot argued that the title was viceregal and represented authority in theory over the entire realm and in fact power second only to that of the king.