St. George for England by G. A. Henty (2002, Paperback)

Set in 1340-56.
The boy-hero of this tale is Walter Somers, a foundling who is reared by a blacksmith who also teaches him the use of a sword. Tall, strong, skilled, and brave, Walter, by a typical Hentyesque providence, meets the Prince of Wales and joins the invasion of Brittany and Flanders. He gives good account as they pile the French dead in front of their line of battle. Walter survives the black death and the Battle of Poitiers, and marries the girl he saved from pirates. This book packs more historical detail into the story than almost any other Heny title. althogether great tale, with the battles of Crecy and Poitiers, I recomend you get the Hard Cover edition, as it will last longer, but Either one, there still the same great story!