Cerberus is an obsolete constellation created by Hevelius in the 17th century, whose stars are now included in the constellation Hercules.
It was depicted as a three-headed snake that Hercules is holding in his hand.
This constellation "figure typified the serpent ... infesting the country around Taenarum the Μέτωπον of Greece, the modern Cape Matapan.
"[1] The presence of Cerberus (Kerberos) at Taenarum (Tainaron) is mentioned by Strabo, Statius, and Seneca the Younger.
[2] John Senex combined this constellation with the likewise obsolete constellation Ramus Pomifer, an apple branch held by Hercules, in his 1721 star map to create "Cerberus et Ramus".