 He was the count who initiated the 14th century expansion of the county.In summer 1337, with the outbreak of the Hundred Years War, he provided a contingent of 6,000 men for the campaign of Raoul I of Eu, Constable of France, in Gascony.In July 1338, he attended a general conference at La Réole, but before achieving anything of note, John and his fellow captain-general in the south, Gaston III, Count of Foix, were called north to help counter the expected invasion of Northern France by King Edward III of England.