Llewelyn still remained under arms.  He had profited by the two years of strife to deal deadly blows against the marchers.  He conquered the Mid-Welsh lands which had been granted to Mortimer, and devastated Edward’s Cheshire earldom.  When Gloucester grew discontented with the course of events, the old friend of Montfort became the close ally of the man who had ruined Montfort’s cause.  A Welsh chronicler treats Gloucester’s march to London as a movement which naturally followed the alliance of Gloucester and Llewelyn.  On Gloucester’s submission, Llewelyn was left to his own resources.  Edward had it in his power to avenge past injuries by turning all his forces against his old enemy.  But the country was weary of war, and Edward preferred to end the struggle.  The legate Ottobon urged both Edward and the Welsh prince to make peace, and in September, 1267, Henry and his son went down to Shrewsbury, accompanied by Ottobon, who received from the king full powers to treat with Llewelyn, and a promise that Henry would accept any terms that he thought fit to conclude.  Llewelyn thereupon sent ambassadors to Shrewsbury, and the negotiations went on so smoothly that on September 25 a definite treaty of peace was signed.  On Michaelmas day Henry met Llewelyn at Montgomery, received his homage, and witnessed the formal ratification of the treaty.

By the treaty of Shrewsbury Llewelyn was recognised as Prince of Wales, and as overlord of all the Welsh magnates, save the representative of the old line of the princes of South Wales.  The four cantreds, Edward’s old patrimony, were ceded to him; and though he promised to surrender many of his conquests, he was allowed to remain in possession of great tracts of land in Mid and South Wales, in the heart of the marcher region.[1] Substantially the Welsh prince was recognised as holding the position which he claimed from Montfort in the days of the treaty of Pipton.  Alone of Montfort’s friends, Llewelyn came out of an unsuccessful struggle upon terms such as are seldom obtained even by victory in the field.  The triumph of the Welsh prince is the more remarkable because Edward and his ally, Mortimer, were the chief sufferers by the treaty.  But Edward had learnt wisdom during his apprenticeship.  He recognised that the exhaustion of the country demanded peace at any price, and he dreaded the possibility of the alliance of Llewelyn and Earl Gilbert.  But whatever Edward’s motives may have been in concluding the treaty, it left Llewelyn in so strong a position that he was encouraged to those fresh aggressions which in the next reign proved the ruin of his power.  The Welsh wars of Edward I. are the best elucidation of the importance of the treaty of Shrewsbury.  The Welsh principality, which Edward as king was to destroy, was as much the creation of the Barons’ War as the outcome of the fierce Celtic enthusiasm which found its bravest champion in the son of Griffith.

    [1] For the growth of Llewelyn’s power see the maps of Wales in
    1247 and 1267 in Owens College Historical Essays, pp. 76 and
    135.