Maintaining unit cohesion

[Watchman]

Generally it was a matter of drill and practice. It's sort of like how armies still drill recruits in assorted as-such pointless group maneuvers out on the drill grounds, just to tech them to react to orders swiftly - something of a leftover from the days when infantry marched in closed lines elbow to elbow, muskets shouldered, in combat.

AFAIK such thorough drill was even more necessary for cavalry, owing to the peculiarities of the way horses maneuver and the fluid and explosive character of mounted combat.