Danae
A doomed king tries to imprison a prophecy.
Many Greek and Roman myths trace royal lineages. The cities are real; the genealogies are legendary. By Ovid's time, the Bronze-Age chieftains behind them were long forgotten.
We've met Cadmus of Thebes. Now we turn to the Argive genealogy. Because the city of Argos was so central, the word "Argive" often functions like "Greek" or "Achaean" in literature.
We've already met Inachus, the river god and mythical founder of Argos. We've also met his daughter Io, whom Jupiter turned into a heifer.
Io produced a line of Egyptian kings: Epaphus (father of Libya), Belus, and Aegyptus. The twin brother of Aegyptus was Danaus, who returned to Greece with his fifty daughters to claim the throne of Argos.
Don't worry if you can't remember every name; the Argive family tree is famously bloated. We'll pick up the lineage three generations later with Acrisius.
Acrisius has just defeated his twin brother Proetus to become king of Argos. He now seeks heirs to secure his power.
Apollodorus
When Acrisius inquired of the oracle how he should get male children, the god said that his daughter would give birth to a son who would kill him.
Fearing that, Acrisius built a brazen chamber under ground and there guarded Danae. Zeus had sex with her in the shape of a stream of gold which poured through the roof into Danae's lap.
When Acrisius afterwards learned that she had got a child Perseus, he would not believe that she had been seduced by Zeus, and putting his daughter with the child in a chest, he cast it into the sea.