We're introduced to Evelyn as Evelyn Carnahan, a librarian and an aspriing Egyptologist. Of course, after the first Mummy movie, Evelyn marries Rick and becomes the lovely Evelyn O'Connell we have her labeled as. She saves Rick's life in the first movie and brings him along on her adventure. The rest is fictional history.
Evelyn: By the way, why did you kiss me? Rick: I don't know. I was about to be hanged. It seemed like a good idea at the time. Evelyn: Ooh! [gets up and walks away in a huff] Rick: [Calling after her] What? What'd I say?