In 1893, the same printer bought several more drawings for Weatherly's "Our Dear Relations", another book of rhymes, and the following year Potter sold a series of frog illustrations and verses for "Changing Pictures", a popular annual offered by the art publisher Ernest Nister. Potter was pleased by this success and determined to publish her own illustrated stories. Whenever Potter went on holiday to the Lake District or Scotland, she sent letters to young friends, illustrating them with quick sketches. Many of these letters were written to the children of her former governess Annie Carter Moore, particularly to Moore's eldest son Noel who was often ill. In September 1893, Potter was on holiday at Eastwood in Dunkeld, Perthshire. She had run out of things to say to Noel, and so she told him a story about "four little rabbits whose names were Flopsy, Mopsy, Cottontail and Peter". It became one of the most famous children's letters ever written and the basis of Potter's future career as a writer-artist-storyteller. In 1900, Potter revised her tale about the four little rabbits, and fashioned a dummy book of it – it has been suggested, in imitation of Helen Bannerman's 1899 bestseller "The Story of Little Black Sambo". Unable to find a buyer for the work, she published it for family and friends at her own expense in December 1901. It was drawn in black and white with a coloured frontispiece. Rawnsley had great faith in Potter's tale, recast it in didactic verse, and made the rounds of the London publishing houses. Frederick Warne & Co had previously rejected the tale but, eager to compete in the booming small format children's book market, reconsidered and accepted the "bunny book" (as the firm called it) following the recommendation of their prominent children's book artist L. Leslie Brooke. The firm declined Rawnsley's verse in favour of Potter's original prose, and Potter agreed to colour her pen and ink illustrations, choosing the then-new Hentschel three-colour process to reproduce her watercolours. On 2 October 1902, "The Tale of Peter Rabbit" was published, and was an immediate success. It was followed the next year by "The Tale of Squirrel Nutkin" and "The Tailor of Gloucester", which had also first been written as picture letters to the Moore children. Working with Norman Warne as her editor, Potter published two or three little books each year: 23 books in all.