Mary had a little lamb is a popular nursery rhyme. It starts

Mary had a little lamb,

its fleece was white as snow.

And everywhere that Mary went

the lamb was sure to go

It followed her to school one day

school one day, school one day

It followed her to shool one day, which was against the rules.

It made the children laugh and play,

laugh and play, laugh and play

it made the children laugh and play to see a lamb at school.

It was first published as a poem by Sarah Hale on May 24, 1830, prompted by the incident described below.

As a girl, Mary Sawyer (later Mrs. Mary Tyler) kept a pet lamb, which she took to school one day at the suggestion of her brother. A commotion naturally ensued. Mary recalled, “Visiting school that morning was a young man by the name of John Roulstone, a nephew of the Reverend Lemuel Capen, who was then settled in Sterling. It was the custom then for students to prepare for college with ministers, and for this purpose Mr. Roulstone was studying with his uncle. The young man was very much pleased with the incident of the lamb; and the next day he rode across the fields on horseback to the little old schoolhouse and handed me a slip of paper which had written upon it the three original stanzas of the poem. . . .” (The Story of Mary’s Little Lamb, Dearborn, 1928, p. 8).

There are two competing theories on the origin of this beloved poem. One holds that Roulstone wrote the first twelve lines and that the final twelve lines, more moralistic and much less childlike than the first, were composed by Sarah Hale; the other is that Hale was responsible for the entire poem.

Thomas Edison recited the first stanza of this poem in testing his invention of the phonograph in 1877, making this the first audio recording to be successfully made and played back. In 1923, Henry Ford moved a building to the grounds of the Wayside Inn from Sterling, Massachusetts, which he believed was the original schoolhouse mentioned in this poem.

The rhyme has gained a rather darker meaning in recent sci-fi as an archetypal mantra against telepathy - focusing on the rhyme helps shield other thoughts from intrusion.