Yeah back in the day when you also had Knights of Solamnia in AD&D to prestige as well. Cavaliers suck now. They don't stack with the Paladin at all unless you're going for the non-spellcasting Paladin from UA. They don't have +1 to spellcasting, which is dumb if they're supposed to be another form of paladin chargers. OR, if you're going as a Knight, have a horse, and are constantly riding into battle. Dungeon adventurers they are not.It dates back to earlier editions of the game in which the Paladin became a subclass of the Cavalier, which was the quintessential mounted combatant.
This was done because so many legendary examples of paladins were horsemen of great skill...mostly because they were raised to be such. Only a few, like Jeanne D'arc (Joan of Arc), achieved their status as Paladin from being born as peasants.
PC I recently played until 22nd level and completed the Savage Tide Dungeon Magazine campaign.


(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.