Ruaidhri and his brother may have accompanied Felim mac Cathal Crobderg Ua Conchobair (reigned 1233–1256), on an expedition to Wales in 1245 under Henry III.
James Hardiman says of him: he found, by experience, that it was safer to rely on the battle-axes of his bold Galloglas (Gallowglass) than on appeals to the sovereign against Anglo-Norman outrage in Ireland.
These years also marked the final eradication of any authority the Ó Flaithbheartaigh had over their original homeland of Uí Briúin Seóla.
Hardiman goes on to say: Before the close of the thirteenth century, the O'Flaherties became masters of the entire territory of Iar-Connacht, extending from the western banks of Lough Orbsen, to the shores of the Atlantic.
Separated from the rest of the kingdom, in that peninsulated, and then almost inaccessible district, they interfered but little in the external transactions of the province, and are, therefore, but seldom noted in our Annals for the two succeeding centuries.