timespace coordinates: 9th century Ireland
It also draws upon Celtic mythology; examples include its inclusion of Crom Cruach, a pre-Christian Irish deity and the reference to the poetic genre of Aislings, in which a poet is confronted by a dream or vision of a seeress, in the naming of the forest sprite encountered by Brendan. Wider mythological similarities have also been commented upon, such as parallels between Brendan’s metaphysical battle with Crom Cruach and Beowulf‘s underwater encounter with Grendel’s mother.
The Secret of Kells began development in 1999, when Tomm Moore and several of his friends were inspired by Richard Williams’s The Thief and the Cobbler, Disney’s Mulan and the works of Hayao Miyazaki, which based their visual style on the respective traditional art of the cultures featured in each film. They decided to do something similar to Studio Ghibli‘s films but with Irish art. Tomm Moore explained that the visual style was inspired by Celtic and medieval art, being ‘flat, with false perspective and lots of colour’. Even the clean up was planned to ‘obtain the stained glass effect of thicker outer lines’. (wiki)