This question already has an answer here:
The primary motivation for the question is the line in Leia's recorder message to Obi Wan "you fought with my Father in the Clone Wars". Was this a throwaway line put in there to give Leia some connection with Obi Wan, suitable since 'clone wars' sounds like something that might happen in the Star Wars Universe? Or did Lucas have the concept of what we now, through the prequels and cartoon, know as the Clone Wars?
I'm looking for, I guess, evidence from interviews, DVD commentary tracks etc.