Before revision: Rogers (1900), p. 279 With a double team there could be two postilions, one for each pair, Rogers (1900), pp 282–283, 107 or one postilion would ride on the left rear horse in order to control all four horses.
After revision: Rogers (1900), p. 279 With a double team there could be two postilions, one for each pair, or, especially in France, one postilion would ride on the left wheel (rear) horse in order to control all four horses.