Fame

Fame is used for two purposes. One is a requirement to equip mounts & flags and the other is a requirement to become Dual Class.

You can gain fame from various quests and dailies as well as donating to your nation. Further, you may buy red envelopes from the mall which will reward you 40 Fame per envelope.

Fame requirements for mount & flag:

Horse:1300
Bull:1600
Phantom Horse:2000
Flag:1500

Fame requirements for Dual Class

Dual Class 4:4000

From the help built into the game client.