Less heavily armoured soldiers were more vulnerable than knights. For example, enemy crossbowmen were forced to retreat at Crécy when deployed without their protecting pavises. Horses were generally less well protected than the knights themselves; shooting the French knights' horses from the side (where they were less well armoured) is described by contemporary accounts of the Battle of Poitiers (1356), and at Agincourt John Keegan has argued that the main effect of the longbow would have been in injuring the horses of the mounted French knights.