Robert Hayden - Perseus

Her sleeping head with its great gelid mass
of serpents torpidly astir
burned into the mirroring shield--
a scathing image dire
as hated truth the mind accepts at last
and festers on.
I struck. The shield flashed bare.

Yet even as I lifted up the head
and started from that place
of gazing silences and terrored stone,
I thirsted to destroy.
None could have passed me then--
no garland-bearing girl, no priest
or staring boy--and lived.

Robert Hayden

http://www.poemhunter.com/poem/perseus/