Page "Heracles" Paragraph 58

Another episode of his female affairs that stands out was his stay at the palace of Thespius king of Thespiae, who wished him to kill the Lion of Cithaeron.

As a reward, the king offered him the chance to make love to his daughters, all fifty of them, in one night.

Heracles complied and they all became pregnant and all bore sons.

This is sometimes referred to as his Thirteenth Labour.

Many of the kings of ancient Greece traced their lines to one or another of these, notably the kings of Sparta and Macedon.