NetDragon Websoft claims that Conquer Online was the world's first free-to-play MMO. Given that it debuted way back in 2003 when MMOs (nevermind F2P) were decidedly uncool, we're a little fuzzy on whether it was in fact the first of its type.
What we do know is that Conquer Online is now available in the iTunes Store, and NetDragon says that the game is "the first ever completely free MMORPG arriving on the iPad; [there's] no charge to download and no monthly subscription fee."
The game is set in ancient China and features six martial arts-based classes, player housing, and plenty of questing and monster-killing. There's even a player marriage mechanic if you tire of more traditional MMO gameplay. We've got a launch trailer for you behind the break, and you'll find more info at the iTunes Store and the game's official website.