Hercules is the Roman name for the mythical Greek hero Heracles, son of Zeus and the mortal Alcmena. Early Roman sources suggest that the imported Greek hero supplanted a mythic Italian shepherd called "Recaranus" or "Garanus", famous for his strength. While adopting much of the Greek Heracles' iconography and mythology as his own, Hercules adopted a number of myths and characteristics that were distinctly Roman.
Hercules' Latin name is not directly borrowed from Greek Herakles but is a modification of the Etruscan name Hercle, which derives from the Greek name via syncope. An oath invoking Hercules (Hercle! or Mehercle!) was a common interjection in Classical Latin.
In Roman works of art and in Renaissance and post-Renaissance art that adapts Roman iconography, Hercules can be identified by his attributes, the lion skin and the club: in mosaic he is shown tanned black, a virile aspect. While he was a champion and a great warrior, he was not above cheating and using any unfair trick to his advantage. However, he was renowned as having "made the world safe for mankind" by destroying many dangerous monsters. His self-sacrifice obtained him the ascent to the Olympian realms and he was welcomed by the gods.
In popular culture the Europeans adopted the Etruscan Hercle, a hero-figure that had already been influenced by Greek culture — especially in the conventions of his representation — but who had experienced an autonomous development. Etruscan Hercle appears in the elaborate illustrative engraved designs on the backs of Etruscan bronze mirrors made during the fourth century BC, which were favoured grave goods. Their specific literary references have been lost, with the loss of all Etruscan literature, but the image of the mature, bearded Hercules suckling at Uni/Juno's breast, engraved on a mirror back from Volterra, is distinctively Etruscan. This Hercle/Hercules — the Hercle of the ejaculation "Mehercle!" — remained a popular cult figure in the Roman legions. The literary Greek versions of his life and works were appropriated by literate Romans from the 2nd century BC onwards, essentially unchanged, but Latin literature of Hercules added anecdotal detail of its own, some of it linking the hero with the geography of the Western Mediterranean. Details of the Greek cult, which mixed chthonic libations and uneaten holocausts with Olympian services, were adapted to specifically Roman requirements as well, as Hercules became the founding figure of Herculaneum and other places, and his cult became entwined with Imperial cult, as shown in surviving frescoes in the Herculanean collegium. His altar has been dated to the 6th or 5th century BC. It stood near the Temple of Hercules Victor. Hercules became popular with merchants, who customarily paid him a tithe of their profits.
Some early emperors took up the attributes of Hercules (eg Traianus), and later Roman Emperors, in particular Commodus and Maximian, went further and often identified or compared themselves with him and supported his cult; Maximianus styled himself "Herculius".
The cult of Hercules spread through the Roman world. In Roman Egypt, what is believed to be the remains of a Temple of Hercules are found in the Bahariya Oasis.
The Romans adopted the Greek stories about Heracles essentially unchanged, but added anecdotal detail of their own, some of it linking Hercules with the geography of the Western Mediterranean.
In Roman mythology, Acca Larentia was Hercules' mistress. She was married to Tarutius, a wealthy merchant. When he died, she gave his money to charity. In another version, she was the wife of Faustulus.
... they say that Hercules, too, once visited them; and when going into battle, they sang of him first of all heroes. They have also those songs of theirs, by the recital of this barditus as they call it, they rouse their courage, while from the note they augur the result of the approaching conflict. For, as their line shouts, they inspire or feel alarm.
Roman era Hercules' Clubs appear from the 2nd to 3rd century, spread over the empire (including Roman Britain, c.f. Cool 1986), mostly made of gold, shaped like wooden apples. A specimen found in Köln-Nippes bears the inscription "DEO HER[culi]", confirming the association with Hercules.
In the 5th to 7th centuries, during the Migration Period, the amulet is theorized to have rapidly spread from the Elbe Germanic area across Europe. These Germanic "Donar's Clubs" were made from deer antler, bone or wood, more rarely also from Bronze or precious metals. They are found exclusively in female graves, apparently worn either as a belt pendant, or as an ear pendant. The amulet type is replaced by the Viking Age Thor's hammer pendants in the course of the Christianization of Scandinavia from the 8th to 9th century.
Roman images of Hercules were based upon Hellenistic Greek images and might be contrasted with the images of Hercules that appear in Attic vase-painting (see Heracles). One aspect of Greek Hercules was not adopted by Roman culture: the ambivalent relationship with his patroness/antagonist Hera that was "Hera's man", Hercules.