 FitzWalter was summoned alongside 43 other Essex knights to muster in Ipswich in December 1338.Armed and ready to fight, FitzWalter joined the retinue of William de Bohun, who had recently been created Earl of Northampton.FitzWalter gained a reputation as a good soldier during Edward III's early campaigns, and he periodically returned to fight in France over the course of his career.