Images Aside
Pack Saddles Aside

The fifth manner is riding without stirrups, using a pack saddle or entirely bareback. The trick here lies in tightening your legs and folding yourself upright versions: first, with the legs extended and tightened at the knees and thighs; second, gathering the legs and squeezing them against the horse; third, squeezing with the entire leg this way, and placing the tips of the feet near the mount's elbows.  (Duarte I, 1438)