Hercules m. Latin Hercules, the Roman form of Greek Ἡρακλῆς, from Greek Ἡρα 'Hera' (the name of a goddess) + Greek κλέος 'report; good report, fame, glory', the name of a son of Zeus.
The ancient Greek and Roman hero was well-known in the Middle Ages for his Twelve Labours. In cultures and contexts where it was not uncommon to name children for figures in important literary and mythical cycles, Hercules was a popular choice.