Cerberus, powerful multi-headed monster
Cerberus (Kerberos) was, according to Hesiod, a powerful frightening monster with fifty heads, serpent's heads around its neck and a dreadful dragon's tail. It had a brazen sounding bark and ate raw flesh. Other authors seem to agree with the description except for the number of heads, instead of fifty, it was generally a three-headed monster. Cerberus was an offspring of Echidna, the monstrous half-woman, half-serpent, and the fearsome giant Typhoeus, often described as the most terrible of all monsters. This lineage links Cerberus to other fearsome creatures such as the Lernaean Hydra and Chimera.
Myths of Cerberus, his loyalty to Hades and encounters
The following grouped sections are available:
The hound and gatekeeper of Hades
It is said that the creature was a loyal hound of the god Hades and its main task was to guard the gates of the underworld, preventing anyone from entering the realm of the dead. Even more important for Cerberus was to prevent any soul from escaping because Hades feared that one would tell about all the horrors of this forsaken place to other gods and mankind. With multiple heads, frightening bark and monstrous appearance, Cerberus was the perfect gatekeeper that, according to Hesiod, no one could overcome. It is also said that the hound would bark so loud that it echoed throughout the entire underworld.
Encounters with gods and heroes
Cerberus symbolized a boundary between the living and the dead and, because of it, there were many encounters with the creature in the classical myths, where one would try to cross that boundary in either hope or despair. One of such encounters was mentioned in Valerius Flaccus' Argonautica, where it is said that Cerberus held back Coeus, where the titan, in his madness, wanted to escape the gloom of the underworld to take revenge on Zeus and take back the rulership of the heavens and earth.
Another such event was when Orpheus was searching for his wife in the underworld. According to Virgil, Cerberus was put in a state of wonder by the song of Orpheus' lyre which made the hound forget to bark and repel the hero from entering the realms of Hades. Aeneas and Psyche have also encountered Cerberus and passed through the gates unharmed, the hero planted honey in a drugged meal which made the creature drowsy while the goddess, in one of the tasks set by Aphrodite, distracted the gatekeeper with barley cakes.
The most famous of encounters with Cerberus was the one with Heracles, where the hero was tasked to bring the creature from the underworld and present it to Eurystheus. When Heracles reached Hades, he asked the god for permission to take the hound. Hades agreed, on condition of mastering it without using weapons. The hero then found Cerberus at the gates of Acheron and flung his arms around its head and, despite being bitten by its tail, continued his grip until the hound stopped resisting and gave up.
Sources
To learn more, you may explore the sources and notes about Cerberus yourself