A lot of sites just say "Enscribed at Thermopylae" on a stone or whatever.
I only saw one webpage that said "attributed."
Most everyone seems to give it solidly to Simonides.
Go tell the Spartans, stranger passing by, that here obedient to their laws we lie.
~Simonides - Epitath on the monument marking the Battle of Thermopylae
The full quote is given by Simonides (5th century BC) as:
"Go, tell the Spartans, thou who passest by,
That here obedient to their laws we lie"
http://www.cs.hut.fi/~pno/Fiction/apf/a ... amids.html
Go tell the Spartans, thou that passest by,
That here, obedient to their laws, we lie.
~Simonides, Tr. William Lisle Bowels
http://www.glaced.digitalspace.net/cgi- ... pylae.html
An epitaph to commemorate the heroic last stand at Thermopylae was written by Simonides: "Go tell the Spartans, thou who passest by, that here obedient to their laws we lie."
http://www.geocities.com/Athens/Acropol ... stands.htm