In an important article Seán Duffy highlighted that John de Courcy, although traditionally described as having hailed from Somerset, in fact had important connections with the north of England, more particularly Cumbria, via his maternal relatives, and that he drew many of the tenants for his lordship of Ulster from that region rather than from Somerest. The filiations of the religious houses which he founded in Ulster similarly reflected a Cumbrian connection. John de Courcy shared with Richard fitz Gilbert, earl/lord of Pembroke/Strigoil, alias Strongbow, and with Hugh de Lacy the distinction of having succeeded to a virtually intact pre-Norman Irish lordship: just as Strongbow succeeded to the lordship of Leinster, and Hugh de Lacy to that of Mide, so John de Courcy acquired the Dál Fiatach kingship of Ulaid. What distinguished de Courcy from either Strongbow or Hugh de Lacy, however, was his status prior to his intervention in Ireland, for, unlike either of these men, John de Courcy, whom Giraldus described as ‘pauperum et mendicum’, was not a tenant-in-chief of the English crown. That distinction had a bearing on the creation, the settlement, and ultimately, also, his loss of the lordship of Ulster.

Just how limited de Courcy's resources were before his intervention in Ireland is reflected in the fact that historians have failed to identify landholdings of de Courcy in England beyond a modest manorial estate in Middleton Cheney in Northamptonshire, which came to him via his maternal relatives.