The Lances of Lynwood by Charlotte M. Yonge

The legacy of a fallen brother rests heavy on the shoulders of young Eustace Lynwood. Thrown into the bloody theater of the Hundred Years' War, he must navigate the treacherous waters of court jealousy and battlefield brutality. His lance must be true, but his heart must be truer still to survive the machinations of false friends. This is an exhilarating chronicle of grit, chivalry, and the hard-won path to becoming a legend.