offered precedents to establish that in the past trials between the lords Marcher 
and Welshmen had been according to the course of the common law, and he 
concluded with the averment that the King was in seisin of pleas in his Curia 
between his Marcher barons and Wales, to wit, before him in his Curia according 
to the common law. To proceed otherwise would be in diminution of the 
royal prerogative. 130 
In their rejoinder, counsel for Llewellyn insisted that both by treaty and as 
a matter of common right the Prince was entitled to Welsh law because every 
province in the King's imperium had its own laws and customs according to 
its own language: the Gascons in Gascony, the Scots in Scotland, the Irish in 
Ireland, and the English in England; all of which was by way of enlargement 
rather than of diminution of the crown. 131 Since it was perfectly apparent 
from what had gone before that to apply Welsh law involved the employment 
of Welsh judges, this averment must be taken as an implicit denial of the 
commissioners' competence. Gruffydd, however, insisted that all the nations 
mentioned were ruled by and proceeded according to a single common law in 
Curia Regis and not by diverse laws in conflict one with another, and he reiterated 
his argument respecting the King's seisin of pleas. 132 
What Gruffydd's contention amounted to was the familiar argument of the 
civilians that in cases of conflicts the law of the judge must prevail. His averments 
respecting the prevalence of the common law, unless taken as a reference 
to the community of English and Irish law or to a common stock of feudal 
usages, was not a correct statement of conciliar practice. On the contrary, it 
appears that in the justiciation of causes which had a political complexion, the 
Curia Regis was indifferent to the provenance of precedents urged upon it. In 
the earlier litigation over the Chester succession one litigant had proffered examples 
from overseas, and presumably had also referred to Roman law; 133 in 
the past Welsh litigants had been allowed Welsh law; 134 and near the end of 
the century one of the claimants to the Scottish throne saw no impropriety in 
urging upon the special tribunal a ius naturale for sovereigns, with a pair of 
130 ibid., 266. 
131 "Quod cum unaqueque provincia sub imperio 
domini Regis constituta habeat leges suas, 
et consuetudines secundum modum et usum 
parcium illarum übi sita fuerit sicut Vasconienses 
in Vasconia, Scotici in Scocya, Yberniensis 
in Ybernia, Anglici in Anglia, quod est pocius 
ad ampliacionem corone domini Regis quam 
ad diminucionem eiusdem, petit idem Princeps 
similiter quod ipse, possit legem suam Walensicam 
optinere, et secundum eandem procedere 
precipue cum dominus Rex in composicione 
pacis inter eos firmata de libera voluntate sua 
sibi et omnibus hominibus Walensicis legem 
suam Walensicam concessit unde cum de lure 
communi debeat habere legem suam et consuetudinem 
Walensicam sicut alie nationes 
predicte sub imperio domini Regis constitute 
suas leges et consuetudines secundum linguam 
suam habent" (ibid.). 
132 "Dominus Rex est in seysina placitandi in 
Curia sua inter Barones suos de Marchia et 
Wallia ut in eadem secumdum legem communem 
procedatur" (ibid.). 
133 Bracton's Notebook, p!. 1227 
134 Davies, Welsh Assize Roll, 16: 1 Calendar of 
Inquisitions, Miscellaneous, no. 1159.