CERBERUS, n. The watch-dog of Hades, whose duty it was to guard the entrance -- against whom or what does not clearly appear; everybody, sooner or later, had to go there, and nobody wanted to carry off the entrance. Cerberus is known to have had three heads, and some of the poets have credited him with as many as a hundred. Professor Graybill, whose clerky erudition and profound knowledge of Greek give his opinion great weight, has averaged all the estimates, and makes the number twenty-seven -- a judgment that would be entirely conclusive is Professor Graybill had known (a) something about dogs, and (b) something about arithmetic. Ambrose Bierce, THE DEVIL'S DICTIONARY

In Greek mythology, Cerberus (from Κέρϐερος, Kerberos, demon of the pit), was the hound of Hades—a monstrous three-headed dog (sometimes said to have 50 or 100 heads), (sometimes) with a snake for a tail and innumerable snake heads on his back.

Cape Tenaro is where Heracles went to find the entrance to Hades (or Άδης in Greek) to fulfill his last labor of capturing Cerberus

Heracles with Cerberus

He guarded the gate to Hades (the Greek underworld) and ensured that the dead could not leave and the living could not enter. His brother was Orthrus.

Cerberus is the offspring of Echidna and Typhon.

He was overcome several times:

Heracles' final labour was to capture Cerberus, which he did by treating it with the first kindness it had ever received.

Orpheus used his musical skills to lull Cerberus to sleep.

In Roman mythology, Aeneas lulled Cerberus to sleep with drugged honeycakes.

In Roman mythology, Psyche also lulled Cerberus to sleep with drugged honeycakes.

In Greek mythology, Hermes puts him to sleep with water from the river Lethe.

He can be found also in Dante's Divine Comedy, in Canto VI of Inferno (third circle).

Cerberus has also made numerous appearances in video games, most notable is the Final Fantasy, Castlevania and Devil May Cry series.

Heracles and Cerberus Louvre F204, Andocides

Zeus with Cerberus and Eagle, British Museum

Cerberus, Albrecht Dürer

Hercules and Cerberus, Peter Paul Rubens

William Blake, Cerberus

Hercules and Cerberus, Francisco de Zurbaran

Hercules Gets Cerberus from the Underworld, Charon the Ferryman of the Styx, Jacob van Campen

Hercules capturing Cerberus, Sebald Beham

In Spanish, cancerbero (from Canis Cerberus, "dog Cerberus") is a Latinate form for gatekeeper, even for a football (soccer) goalkeeper.

See also

Cerberus, The Dog of Hades, The History of an Idea by Maurice Bloomfield

Cerberus in Stamps

Psyche and Cerberus , Edmund Dulac (1882-1953)

The Cerberus

Devil May Cry 3: Dante's Awakening, in this game, Cerberus is a boss in the third mission, a metaphor to Dante's Inferno in Canto VI

God of War, a game where some foes are small dogs that, when left undefeated for too long, transform into Cerberus-like creatures.

The Greek Underworld
Residents:
Persephone Hades Minos Aeacus	Rhada- manthys Charon Cerberus
Geography:
Acheron Cocytus Tartarus Lethe	Styx Phlegethon Asphodel Erebus
Famous inmates:
Ixion Sisyphus	Tantalus The Titans