Who was the Rocky character based on?

According to wikipedia:
" Sylvester Stallone's original concept for Rocky, and the character Rocky Balboa, was inspired by his viewing of a fight between Muhammed Ali and Chuck Wepner. The idea of an underdog going the distance and putting up a fierce fight against all odds appealed to Stallone. "
Wikipedia also says that the character Apollo Creed was 'loosely' based on Muhammed Ali.