I’ve been looking for this poem for years! I first saw it at The British Museum’s Aztec exhibition ages ago and found it recently in the old photos. The poem is by Cacamatzin, the Aztec ruler of Texcoco (source here). Cacamatzin was more of a poet than a ruler and was murdered during the Spanish invasion. He sensed his impending death. His poem is about impermanence of our existence, regardless of status or achievements.

‘Who is spared in the end from leaving?
Despite all his gold and his jade,
is a man not bound to go there?
Am I a shield set with turquoise?
A stone secured in a mosaic?
Will I ever walk this earth again?
Will they shroud me in fine mantles?
Here on earth, I think of those
who ruled before me, as the place
of sounding drums draws near.’