Which one thing did the mongol warriors did not do?

Transfer of troops between units was forbidden. The leaders on each level had significant license to execute their orders in the way they considered best. This command structure was highly flexible and allowed the Mongol army to attack en masse, divide into smaller groups to encircle their enemies and either lead their them into an ambush or divide them into small groups of roughly 10 to mop up a fleeing and broken army. Although they fought as a unit, individual soldiers were responsible for their equipment, weapons, and up to five mounts. Their families and herds would accompany them on foreign expeditions.