Most of the characters are historical characters from 3 kingdoms, but most of the "historical events" are fake. I'll point out the significant events
- Burning Cao Cao's ships in Red Cliff WAS NOT Zhuge Liang's idea, IT WAS all Zhou Yu's Idea
- Borrowing arrows with scarecrows and summoning eastern wind by Zhuge Liang is simply fictional
- Liu Bei, Guan Yu, and Zhang Fei ARE NOT sworn brothers
- Zhuge Liang was more credited as a politican instead of a "military strategist"
- Zhou Yu was never jealous of Zhuge Liang, AT ALL, he died due to sever illness instead of getting pissed to death
- Guan Yu did not kill Wen Chou and Hua Xiong, Hua Xiong got killed by Sun Jian's forces while Wen Chou got killed by Cao Cao's forces
- Liu Bei DID owe JinZhou to Wu, Zhou Yu conquered the whole JinZhou after The Battle of Red Cliff AND lend it to Liu Bei
- Diao Chan is simply a fictional character, the murder of Dong Zhuo was planned by Wang Yun and Lu Bu
anyway here are the significant ones, i can list more...-_-
if you want to know more about 3 kingdoms history, read "san guo zi"