Erechtheus was a mythical figure of ancient Athens
. Erechtheus along with Cecrops
was considered as the ancestral figure of Athens
He was traditionally associated with Poseidon but he was occasionally viewed as an ancient king of Athens.
Homer tells us that he was autochthonous, and that he was taken by Athena and placed in her sanctuary, he was worshipped with sacrifices of rams and bulls. His cult name of Poseidon Erechtheus, may refer to him having a personality like Poseidon the earthshaker.
Erechtheus as a king is often credited with a war against Eleusis. He won the war personally by defeating and killing the Eleusinian leader Eumolpus. Unfortunately for Erechtheus Eumolpus was the son of Poseidon, and the Odyssey shows us that Poseidon was a protective parent. Erechtheus was killed almost immediately after killing Eumolpus when he was hit by Poseidon's trident. On his death he was succeeded by his son King Cecrops the second.