Conversation so far:
Why did Superstar Billy Graham return to the WWWF?
Graham returned to the WWWF in April 1977 after an agreement with promoter Vincent J. McMahon
What was Superstar Billy Graham's agreement with McMahon?
How did people respond to Superstar Billy Graham's return?
What else happened to Superstar Billy Graham during 1977-1981?
Graham defeated Bruno Sammartino for the WWWF Heavyweight Championship on April 30, 1977.

Question: What happened after he defeated Bruno?
Self-contained rewrite: What happened after Superstar Billy Graham defeated Bruno?