Hercules is the Roman name for the Greek divine hero Heracles. He was the son of Zeus (Jupiter in Greek) and the mortal Alcmene. In classical mythology, Hercules is famous for his strength and for his epic adventures.
As the mythical embodiment of masculinity and physical power, Hercules was virile beyond measure. King Thespios, desiring grandchildren sired by the demigod, invited Hercules to stay at his palace before a lion hunt. Nine months later, Hercules had 49 new kids. Plutarch, the Greek historian (and eventual Roman citizen), wrote that Hercules' list of male lovers was beyond numbering. Notable standouts were Philoctetes, who upon Hercules' death inherited his bow and arrows, Iolaos of Thebes, Hylas of Argos, and Nestor, the youngest son of King Neleus.
Much of the mythology of Hercules revolves around his many relationships with both men and women, though this aspect of sexuality is not often discussed when talking about Greek Mythology now.