At the Battle of Red Cliffs, Eastern Wu and Liu Bei joined forces to defeat Cao Cao.
Tips
usage
Called 'Eastern' Wu because it held the land east of the Yangtze, and to tell it from the older state of 吴. In poetry it is the Suzhou region itself, as in 杜甫's 门泊东吴万里船 ('at my gate are moored boats come ten thousand li from Wu').
culture
The name lives on in 东吴大学 (Soochow University), founded in Suzhou in 1900 and refounded in Taipei in the 1950s.