In less than a year, he married Ida de Saint Amand, younger daughter and coheiress of Amaury de Saint Amand, 3rd Baron Saint Amand (1341–1402).
He fought at the Battle of Agincourt, and is listed on a pipe-roll with a retinue of 14 lancers and 40 archers.
Next year, the Earl of Warwick, who was Captain of Calais, sent out an expedition on 24 September 1416 to capture a Genoese carrack, since the Genoese were allies of France.
Thomas West was mortally wounded putting on his armoUr before the battle; he was arming himself at the foot of the mast when one of the stones being hauled up to the catapults on the masthead slipped; but he survived long enough to die in England.
The Gesta Henrici Quinti puns in describing the manner of his death, suggesting that he received the chief of all evils (verticem mali) while pursuing the root of all evil (radicem mali).