If “Mary Had a Little Lamb” was published today, it would have a subtext on the cover “inspired by true events.” There actually was a Mary — her last name Sawyer, who one day brought her pet lamb to school. The animal caused a commotion among the kids, and had a particular impression on a young man named John Roulstone, who came back the next to hand Mary a paper with the first four lines of a poem called “Mary’s Lamb.”

On this day, May 24, in 1830, “Mary had a little lamb,” written Sarah Josepha Hale, was published for the first time, as a standalone poem by the Boston publishing firm Marsh, Capen & Lyon.

Hale said the event of Mary’s lamb and John inspired her to write the poem, although some still believe that Hale and Mary were one and the same. As Hale pointed out in one of her last letters, “the incident of an adopted lamb following a child to school has probably occurred many times.”