Twelve gods, but which twelve?
The Twelve Olympians are the main gods of the Greek pantheon, named for Mount Olympus, where they were imagined to live. The most common list runs: Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus and Hermes, plus either Hestia or Dionysus. The final place is the sign that the list was never fixed. Some sources include Hestia, goddess of the hearth, and others replace her with Dionysus, and Hades is normally left out because he belonged to the underworld and not to Olympus. The Greeks recognised the idea of a group of twelve, but not one official roster.
Where the twelve come from
Homer and Hesiod speak of many gods and give no list of twelve. The grouping as a unit seems to appear in cult and later, in art and literature. A famous example is the Altar of the Twelve Gods in the Athenian agora. According to Thucydides, the altar was dedicated by Peisistratus, the grandson of the tyrant of the same name, in the late sixth century BCE, when he held office as archon. In antiquity it became a recognised centre of Athens, and later writers refer to it as a point from which distances were measured, and as a place of refuge for suppliants.
Elsewhere, the number twelve appears in Greek cult in other ways. At Olympia, tradition spoke of altars shared among the twelve gods in pairs, with six altars for the twelve, though details come from later sources and should be taken as tradition. The Parthenon frieze in Athens shows a group of seated gods, often identified as the Olympians, though the identifications of some figures are debated. The Romans had a comparable group, the Dii Consentes, a council of twelve gods, six male and six female, whose statues stood in the Forum, and the Latin poet Ennius gave a couplet naming them. The Roman list pairs Greek gods with Latin counterparts, such as Jupiter, Juno, Minerva and Mars.
Why twelve? The sources do not say. A group of twelve is easy to organise in pairs of male and female deities, and twelve was already a common number for months, hours and tribes in the region. Modern writers sometimes connect the Twelve Olympians to the twelve months or to the zodiac, but there is no ancient evidence that the Greeks designed the group that way, and the zodiac in its present form reached Greece from Babylonian sources only in later centuries. The mention of twelve in astrology is a separate system. Likewise the twelve tribes of Israel and the Twelve Apostles belong to other traditions and were not borrowed from the Olympians.
Heracles and his labors
Heracles, the son of Zeus and the mortal Alcmene, is the great hero of Greek myth. According to the standard story, Hera caused him to go mad and kill his children, and in atonement he was made to serve King Eurystheus of Tiryns and Mycenae, who set him a series of labors. The usual twelve are:
- Killing the Nemean lion
- Killing the Lernaean Hydra
- Capturing the Ceryneian hind
- Capturing the Erymanthian boar
- Cleaning the stables of Augeas
- Driving off the Stymphalian birds
- Capturing the Cretan bull
- Taking the mares of Diomedes
- Fetching the belt of Hippolyta
- Driving off the cattle of Geryon
- Obtaining the apples of the Hesperides
- Bringing back Cerberus from the underworld
Heracles was famous long before the number was fixed. Early poetry and vase painting show him performing many feats, and the number twelve seems to have settled during the fifth century BCE. The temple of Zeus at Olympia, built around the middle of that century, carried twelve metopes, the sculptured panels above the outer columns, showing his labors, which is the first firm evidence for the canonical twelve. The fullest surviving list comes from the Library attributed to Apollodorus, probably of the first or second century CE. Apollodorus says that Eurystheus refused to count two of the tasks, the Hydra because Heracles had help and the stables because he was to be paid, and so two more were added to make twelve. That story suggests that twelve was a target the tradition aimed for, not a number the myth began with. Even so, it is a later account, and the order of the labors varies between sources.
The gods and the hero together
Heracles is a hero who becomes a god. After his death on the pyre at Mount Oeta, Greek myth says he was taken up to Olympus and given immortality. In some accounts he marries Hebe, goddess of youth, and joins the divine circle. Whether he ever occupied one of the twelve places is not established, and his case is better seen as an example of how the line between hero and god could move. Heracles also received his own cult at many places, as a hero and as a god, which is an example of the double status the Greeks sometimes recognised.
Reading the number
Twelve in Greek religion should not be treated as a sign of cosmic design. The group of twelve gods and the twelve labors share a number, and the two stories may have reinforced each other, but the evidence for a deliberate link is thin. Later writers, especially in the Hellenistic and Roman periods, sometimes read the labors as a journey through the zodiac or as the sun’s yearly path. These are interpretations of a later age and are not found in the earliest sources. Today, the safest statement is that twelve was a convenient and respected number in Greek religion, one that fitted a council of gods and a hero’s series of tasks, and that both appear in their fixed form only after a period of change.