In the greek mythology the milky way was created with the milk of the goddess Hera (galaxias in breek means milk). The story goes as follows. Herakles (Herkules in the roman mythology) was the son of Zeus and the mortal Alkamene. In order to obtain mortality young Herakles had to drink the milk of a goddess. Zeus, not being particularly sensitive, placed Herakles on Hera's breast. Zeus suckled quite vigorously thus awakening Hera. She vehemently pushed him away, and milk squirting from her breasts created the milk way.
Hera, the sister and wife of Zeus, was the protector of marriage and the goddess of birth and deliveries. She displayed quite some jealosy towards Zeus's children with immortals. She slowed down the birth of Herakles to favor Eurystheus to become king of the Argives. Later she placed snakes in Herakles's cradle (he strangled them right away) and imposed insanity on him (he killed his sons from the marriage with Magara).

Both Rubens and Tintoretto captured this myth in stunning paintings. T