Zagreus, Ζαγρεύς / Zagreús, was identified with the god Dionysus and was worshipped by followers of Orphism.

According to the followers of Orphism, Zeus had lain with either Demeter or Persephone in the form of a snake. The result of their union was Zagreus. Zeus had intended Zagreus to be his heir, but a jealous Hera persuaded the Titans to kill the child.

The Titans distracted Zagreus with toys, then carried him away and tore Zagreus to pieces. When the Titans were finished, nothing was left but Zagreus' heart, which Athena rescued and gave to Zeus. From the still-beating heart, Zeus made the body of the mortal Semele. The child was eventually born again, despite Hera's intervention. Some accounts say that he was reassembled and resurrected by Demeter; others, that Zeus fed his heart to Semele in a drink, making her pregnant with Dionysus.

Semele, daughter of Cadmus and Harmonia, was the mother of Dionysus (the god and his votaries were both identified as "Bacchus") by Zeus, in one of the two parallel origin-myths of Dionysus. The name Semele, like other elements of Dionysiac cult (thyrsus, dithyramb) are manifestly not Greek (Burkert 1985), apparently Thraco-Phrygian (Kerenyi 1976 p 107; Seltman 1956); the myth of Semele's father Cadmus gives him a Phoenician origin.

Zeus's consort, Hera, a goddess jealous of usurpers, discovered the affair when Semele was pregnant. Appearing as an old crone, Hera befriended Semele, who confided in her that her husband was actually Zeus. Hera pretended not to believe her, and planted seeds of doubt in Semele's mind. Curious, Semele demanded of Zeus that he reveal himself in all his glory as proof of his godhood. Though Zeus begged her not to ask this, she persisted and he agreed. Mortals, however, cannot look upon a god without dying, and she perished, consumed in flame (Ovid, Metamorphoses III.308-312; Hyginus, Fabulae 179).

Zeus rescued the fetal Dionysus, however, by sewing him into his leg (the "Insewn" epithet of the Homeric Hymn). A few months later, Dionysus was born. This leads to his being called "the twice-born" (Apollodorus iii.4.3;Apollonius Rhodius,iv.1137).
When he grew up, Dionysus rescued his mother from Hades, and she became a goddess on Mount Olympus, with the new name Thyone, presiding over the frenzy inspired by her son Dionysus.

The most usual setting for the story of Semele is the palace that occupied the acropolis of Thebes, called the Cadmeia. When Pausanias visited Thebes in the 2nd century AD, he was shown the very bridal chamber where Zeus visited her and begat Dionysus. Since a seal inscription found at the palace can be dated 14th-13th centuries BC, the myth of Semele is Mycenaean in origin, pre-Hellenic. At the pre-Hellenic site of Lerna, Dionysus descended to Tartarus to free his once-mortal mother.

Though the Greek myth of Semele was localized in Thebes, the fragmentary Homeric Hymn to Dionysus makes the place where Zeus gave a second birth to the god a distant one, and mythically vague:

"For some say, at Dracanum; and some, on windy Icarus; and some, in Naxos, O Heaven-born, Insewn; and others by the deep-eddying river Alpheus that pregnant Semele bare you to Zeus the thunder-lover. And others yet, lord, say you were born in Thebes; but all these lie. The Father of men and gods gave you birth remote from men and secretly from white-armed Hera. There is a certain Nysa, a mountain most high and richly grown with woods, far off in Phoenice, near the streams of Aegyptus..."

Semele was worshipped at Athens in the Lenaia, when a yearling bull, emblematic of Dionysus, was sacrificed to her. One-ninth was burnt on the altar in the Hellenic way; the rest was torn and eaten raw by the votaries (Graves 1960, 14.c.5).
When the initiatory cult of Dionysus was imported to Rome, shortly before 186 BCE, to great public scandal,[1] Semele's name was rendered Stimula. The groves in which the initiation rites took place were deemed sacred to Semele/Stimula. Ovid's Fasti, vi. 503, shifts the origin of the Bacchanalian rites in Rome to a mythic rather than a historic past:

"There was a grove: known either as Semele’s or Stimula’s:
Inhabited, they say, by Italian Maenads.
Ino, asking them their nation, learned they were Arcadians,
And that Evander was the king of the place.
Hiding her divinity, Saturn’s daughter cleverly
Incited the Latian Bacchae with deceiving words:"

Following the Renaissance, the story of Semele formed the basis for the secular oratorio, Semele (1744) by George Frideric Handel and for the operas, Semele by Marin Marais (1706) and John Eccles (1707).

Zeus then obliterated the Titans to ashes with his thunderbolt, and from the ashes came mankind. The ashes explained the mix of good and evil in humans, for humans possessed both a trace of divinity as well as the Titans' maliciousness. [citation needed]

The Orphics believed in the transmigration of souls and that a person was able to remove their intrinsic evilness by living three virtuous lives. Afterwards, they would dwell in Elysium forever.