has the leader of the army been honored with any rank?
Yes, he was a Breton knight.
Bertrand du Guesclin
Bertrand du Guesclin (c. 1320 – 13 July 1380), nicknamed "The Eagle of Brittany" or "The Black Dog of Brocéliande", was a Breton knight and an important military commander on the French side during the Hundred Years' War. 
when did the battle of pontvallain take place? 4 December 1370 who battled against whom? French army and  English force. who led the former? Bertrand du Guesclin who won the battle? The French army.
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Bertrand du Guesclin [SEP] Introduction
Bertrand du Guesclin (c. 1320 – 13 July 1380), nicknamed "The Eagle of Brittany" or "The Black Dog of Brocéliande", was a Breton knight and an important military commander on the French side during the Hundred Years' War. From 1370 to his death, he was Constable of France for King Charles V. Well known for his Fabian strategy, he took part in six pitched battles and won the four in which he held command.