Robert Herrick - ORPHEUS

Orpheus he went, as poets tell,
To fetch Eurydice from hell;
And had her, but it was upon
This short, but strict condition;
Backward he should not look, while he
Led her through hell's obscurity.
But ah! it happen'd, as he made
His passage through that dreadful shade,
Revolve he did his loving eye,
For gentle fear or jealousy;
And looking back, that look did sever
Him and Eurydice for ever.

Robert Herrick

http://www.poemhunter.com/poem/orpheus-3/