David Almond was inspired to write Skellig by his own experiences as a child. He grew up in the north of England, in a town that was very similar to the one in the book. He also had a very close relationship with his grandmother, who told him stories about fairies and other mythical creatures. These experiences helped to shape the world of Skellig, and to create a story that is both magical and believable.
In addition to his own experiences, Almond was also influenced by the work of other writers, such as J.R.R. Tolkien and C.S. Lewis. These writers helped to show him that it was possible to create believable fantasy worlds that were still relevant to the real world. He also drew inspiration from the art of Edward Hopper, whose paintings often depicted lonely and isolated figures.