In Lastwall, serving in the army is not only expected, but respected by all. For those serving in the army, becoming a part of the cavalry is achieving the highest prestige in the realm. Cavaliers, paladins, and fighters are among those that are drawn to this career path most often, with rangers sometimes becoming battle chargers as well.
Key to this class is of course fighting from atop a mount and wielding lance or sword. Of course, mounts cannot be taken inside caverns and buildings, so battle chargers gain a few abilities that help them while unmounted as well.
Sources: Pathfinder Chronicles Campaign Setting, Complete Warrior