Orpheus he went, as poets tell, <br />To fetch Eurydice from hell; <br />And had her, but it was upon <br />This short, but strict condition; <br />Backward he should not look, while he <br />Led her through hell's obscurity. <br />But ah! it happen'd, as he made <br />His passage through that dreadful shade, <br />Revolve he did his loving eye, <br />For gentle fear or jealousy; <br />And looking back, that look did sever <br />Him and Eurydice for ever.<br /><br />Robert Herrick<br /><br />http://www.poemhunter.com/poem/orpheus-3/