I think a lot of us forget that the Grimm Brothers were writers, but their folk tales were collected. Some, were rewrites of the tales already collected by Charles Perrault two hundred years earlier.
Born in Touraine, France, he came from a prestigious family; his elder brother Claude was an architect and member of the Academy of Sciences. Charles became a lawyer and worked as a Clerk for his brother Pierre, and from there he worked his way through government service and up through society, and was at least partially responsible for the design of the maze in the Gardens of Versailles.
But we are interested in his later life when he decided to dedicate himself to his children and his writing.
In 1697, he published Tales and Stories of the Past with Morals (Histoires ou contes du temps passé, avec des moralités), better known as Tales of Mother Goose. The stories included The Sleeping Beauty, Little Red Riding Hood, Puss in Boots, Cinderella, and many more that we know and love to this day, though we often think of the later versions by the Brothers Grimm.
The Morals bit of the title referred to the little rhyming poems at the end of each tale. For instance, in Little Red Riding hood, the poem warns of the danger of pretty girls flirting with someone who may turn out to be an evil wolf.
It is not clear where the stories came from. It is possible he wrote some, but many were older tales which he reworked. There is a myth that he heard these from a children's nurse, but this is possibly not true. Sleeping Beauty, for instance, might well have been based on The Jealous Princess by Camus.
These weren't children's stories as such, but really that was because the idea of literature especially for children did not exist in the seventeenth century. The volume was dedicated to the King'e niece, Élisabeth Charlotte d'Orléans, who was in her early twenties.
One way or another, we probably owe Perrault rather a lot!