An excerpt from a piece in the (Carnegie Mellon) Tartan:

Merwin has been translating works from other languages nearly as long as he has been publishing his own work, across multiple languages and time periods. He offered to the audience only one small translated work, what is said to be the only poem ever written by the emperor Hadrian of Rome. Merwin said that this was a poem he frequently returned to for its simplicity and beauty, a poem so elegant that he didn’t believe it could truly be the only poem written by this man, though possibly the only one saved.

... I'm assuming what Merwin presented was this:

Little soul little stray
little drifter
now where will you stay
all pale and all alone
after the way
you used to make fun of things

Taken from a page at Poetry Magazine with some commentary by Merwin. Here's the Latin ... from HA Had. 25 (via the Latin Library):

animula vagula blandula,
hospes comesque corporis,
quae nunc abibis in loca
pallidula rigida nudula
nec, ut soles, dabis iocos!

... said to be written as he (Hadrian) was dying.