A piece of doggerel out of my past that I can't get out of my mind. 
Can you identify it?
"Romulus and Remus sailed a soapbox down the Tiber, 
And all went well till Romulus tacked, 
And Remus didn't jibe her.  
Three times they sank, three times they rose, 
The fourth they rose no more, 
And then the mother wolf dove in 
And brought them back to shore.  
If the wolf had minded her business, 
Then Rome would be unsung, 
And we today would have no cause 
To curse the Latin tongue."

Hello friendkierstead,

I found the following excerpt which suggests that Romulus and Remus
were the mythical founders of the ancient city of Rome:
"Amulius, fearing that the boys would grow up to overthrow him, had
them placed in a trough and thrown into the River Tiber. At that time
the river was in flood, and when the waters fell, the trough, still
containing the two boys, came ashore. They were found by a she-wolf
who, instead of killing them, looked after them and fed them with her
milk."
Romulus & Remus
http://www.iol.ie/~coolmine/typ/romans/romans9.html

Searching for words like 'soapbox Romulus Remus' or 'unsung Romulus
and Remus' did product any useful results. I am guessing that someone
made a short variation of the poem "Aeneid" by Virgil or wrote their
own poem about Romulus and Remus.

Hopefully this information will have some use to you. I wasn't sure if
you would accept this as an answer, so am posting it in the comments
section. Perhaps another researcher will be able to help you find the
exact source of the poem.

tisme-ga

Tisme is correct. Your poem is the *very* short version of the Roman
myth of Romulus and Remus. They are the twin sons of the war god,
Mars, and are (in the story) founders of Rome.