Sir Robert Knowles’s expedition of 1370 was as futile as that of Lancaster.  He advanced from Calais into the heart of northern France.  Taught by long experience the danger of joining battle, the French allowed him to wander where he would, plundering and ravaging the country.  Roughly following the line of march of Edward III. in 1360, the English advanced through Artois and Vermandois to Laon and Reims, and thence southwards through Champagne.  Then striking northwards from the Burgundian border, they appeared, at the end of September, before the southern suburbs of Paris.  To dissipate the alarm felt at the presence of the English, Du Guesclin was summoned from the south and made constable of France.  Before his arrival Knowles had moved on westwards ’towards the Beauce, intending to reach his own estates in Brittany for winter quarters.  But his young captains got out of control.  Led by a Gloucestershire knight, Sir John Minsterworth, “ready in hand but deceitful and perverse in mind,” a considerable section of the troops refused to follow the old “tomb-robber” to Brittany, and determined to spend the winter where they were, under Minsterworth’s leadership.  Knowles would not give place to his subordinate, and made his way to Brittany with the part of his army which was still faithful to him.  No sooner was he well started than Du Guesclin, after a march of ninety miles in three days, fell upon his rearguard at Pontvallain in southern Maine and overwhelmed it on December 4, 1370.  Knowles managed to reach Brittany with the bulk of his forces, and Minsterworth, the real cause of the disaster, ventured to go to England and denounce his leader as a traitor.  He was forced to flee to France, where he openly joined the enemy.  Seven years later he was captured and executed.

Minsterworth was not the only traitor.  In the earlier part of the war, there had fought on the English side a grand-nephew of the last independent Prince of Wales, Sir Owen ap Thomas ap Rhodri,[1] whose grandfather, Rhodri or Roderick, the youngest brother of the princes Llewelyn and David, had after the ruin of his house lived obscurely as a small Cheshire and Gloucestershire landlord.  In 1365 Owen was in France, engaged, no doubt, in one of the free companies, and on his father’s death he returned to defend his inheritance from the claims of the Charltons of Powys.  Having succeeded in this, he returned to France, and nothing more is heard of him until after the renewal of the war.  In 1370 he appeared as a strenuous partisan of the French.  Mindful of his ancestry he posed as the lawful Prince of Wales, and established communications with his countrymen, both in France and in Wales.  Anxious to stir up discord in Edward’s realm, the French king gladly upheld his claims.  A gallant knight and an impulsive, energetic partisan, Sir Owen of Wales soon won a place of his own in the history of his time.  In Gwynedd he was celebrated as Owain Lawgoch, Owen of the Red Hand.  Conspiracies