I’m not sure of the exact account you’re recalling, but there are a few medieval anecdotes where a lone cavalryman’s charge or flanking maneuver caused a rout simply because the opposing line was already tense or poorly arranged. The key, I think, is that the rider exploited a seam in the formation—perhaps a gap where the archers were turning, or a spot where the infantry was uncoordinated after a failed feint. By moving with speed and precision, the rider created a ripple effect; the soldiers on either side scrambled to fill the hole, breaking the cohesion of the whole line. In those moments, the tactics were less about grand strategy and more about exploiting a momentary weakness with sheer momentum. It’s a reminder that even in a disciplined army, a single lapse can unravel everything if the opponent seizes the chance.