Phoroneus 
 
The river-god, Inachus, was the son of the Titans Oceanus and Tethys. Inachus was the first inhabitant of Argolis. The Inachus River flow the valley of Argolis to the Gulf of Argolis. Inachus married a nymph named Melia, and became the father of two sons, Phoroneus and Aegialeus, and of possibly two daughters, Io and Mycene.

Poseidon and Hera sought to be the patron deity of Argos or Argolis. They asked the Inachus and two other river-gods to act as judges. They awarded the land or city to Hera. Enrage over losing to his sister, Poseidon caused the rivers to dry up. Sometimes, Poseidon would flood the valley of Argolis.

Some says that Io was Inachus' daughter, while there are couple of other possibilities. Io was said to be the daughter of Iasus, or of Peiras (Hesiod called him, Peiren).

His daughter, Io, who was seduced by Zeus and persecuted by the god's jealous wife, Hera, fled Argolis in a form of a cow. Io suffered many hardships, until she finally reached Egypt. Zeus changed her back to her form. There she bore a son, named Epaphus, to Zeus.

Io then married the king of Egypt, Telegonus. Her descendants would later return to Greece and found two powerful kingdoms in Thebes and in Argolus (the last which includes Argos, Tiryns and Mycenae). See Danaans.

For the full story of the hardship of Io, read Heroines.

For now, we'll turn our attention to Inachus' descendants from the Phoroneus' line.

Inachus, as I had said before, was the first inhabitant of Argolis. He was the son of Oceanus and Tethys, and he the river-god of the Inachus River. Most authors say that Inachus was the father of Io, though she was also known to be daughter of Iasus or that of Peiras, by other authors. Because of her involvement with Zeus, she later lived in Egypt, until her descendants returned back to Greece. See the genealogy, on the Early Houses of Argos.

Either Argos was founded either by Inachus or by his son, Phoroneus, which the city was first named as Phoronea.

Phoroneus had married a nymph, who was named Teledice or Cinna, and became the father of Apia and Niobe. Phoroneus also married Cerdo, and he was the father of Car. Car had migrated to Megara, where he founded the citadel, Caria.

Inachus also had a son named Aegialeus, but he died childless. The whole region of Argolis, including Sicyonia, Achaea and the Isthmus was named Aegialeia. He had also founded the city of Aegialeia, which was later changed to Sicyon.

Phoroneus' son, Apis, who had named the whole Peloponnesian peninsula to Apia, died childless. His death was the result of the plot Telchis and Thelxion, because his rule was brutal. Apis was so cruel and brutal, people referred to him as a tyrant.