The taskmaster in the story of Cupid and Psyche was Cupid's mother, the love goddess Venus or Aphrodite. Venus had never liked Psyche, so the opportunity of putting her to a series of tests gave Venus a chance to demand the seemingly impossible. In order for Psyche to win back her husband, Cupid, Venus set 4 seemingly impossible tasks before Psyche:
- sorting out a huge pile of seeds
- retrieving the Golden Fleece,
- filling a flask from the water that fills the River Styx, and
- returning from the Underworld with a box of the beauty ointment of Proserpina (aka Persephone).
There are more details behind it and how she has done it.
There is also this video from TED-Ed telling a smaller part of the story. (Which does not include the 4th task, I don't know why but it doesn't.)
Why did Venus ask her to do these specific tests and what has Psyche learned from them? I want to know the meaning behind these tests.