Historians Geoffrey Keating and T. F. O'Rahilly differ suggesting that it is Munster, not Leinster, that formed two of the fifths. These two fifths were called by Keating: (eastern Munster) and (western Munster), both named after their respective king. Eoin MacNeill discounts this suggestion citing the , which makes mention of as king of all Munster, with simply a "great Munster hero". He also cites that the makes mention of the four fifths of Ireland that waged war on Ulster, which made reference to only one Munster. Another reason given by MacNeill was a problem made by Keating himself. According to Keating, when the province of was being founded, it was created from portions of each province which all met at the hill of Uisnech. The boundaries given by Keating himself for the five provinces however meant that this would have been highly unlikely, with the boundary between his Munster fifths nowhere near this area.