The Storytellers were a species with "weird, unknowable mesmeric powers" who thrived on the belief of others. They used their powers to tell enthralling stories which generated belief. The Fifth Doctor theorised that they fell to Earth from another dimension.
For many centuries, the Storytellers travelled across the planet telling stories. However, humans grew more cynical and lost some of their belief in the stories of the Storytellers, causing the species to begin to die.
By the Middle Ages, Grayling Frimlish was the last surviving Storyteller. The Fifth Doctor and Vislor Turlough encountered Frimlish near the end of his life and witnessed the beginning of his final story-telling in Talespinner Square. (AUDIO: The Last Fairy Tale)