Re Agincourt. The ground was so muddy that the French armoured knights had to walk their horses rather than charge. That's not the same as fighting on foot -

Re Agincourt. The ground was so muddy that the French armoured knights had to walk their horses rather than charge. That's not the same as fighting on foot - or at least, not until your mount has been killed beneath you by English and Welsh longbowmen raining arrows on your densely packed (and slow-moving) forces.