The Greek hero Heracles (Hercules to Romans) had a pet lion - Apparently.
In Greek mythology, Heracles was said to have tamed the Nemean Lion, a ferocious beast with a impenetrable coat of hair. However, the myth also mentions that Heracles later befriended the lion, keeping it as a loyal companion. The story of the Nemean Lion is featured in Robert Graves' book "The Greek Myths" and is also found in the ancient Greek texts of Apollodorus and Diodorus Siculus.