Question

I had a mistress, with beauty and grace,
With a curious hand and fair to face.
She was the first on earth, and made of clay.
I was a gift to Epimethius on their wedding day.
The Gods, they wanted her to let me be.
But none of their warnings did she heed.
You see, my mistress was alone one day,
When to me her inquisitive hand did stray.
She gave you sickness, destruction and greed,
And all of the things from which evil does feed.
But do not be angry, do not mope.
The last she gave you? It was hope.
What am I and who was my mistress?