The Book of Kells was probably begun in the Columban monastery of Iona, off western Scotland, and brought to the abbey of Kells in Ireland in the early ninth century to escape Viking raids. It is a 340-folio vellum manuscript carrying the text of the four Gospels. The text is Latin Vulgate; but the book's distinction is not in its text but in the visual programme woven around it.

Every page is in motion. Animal figures stretch their tails to wrap their own letterforms; human and angelic figures dissolve into spiralling interlace. Tight geometric motifs — the Celtic spirals and knots — sit on the same page as the figures and at equal weight. The separation between abstract ornament and representational figure collapses. The colours are not gold but pigments of incomparable brilliance: lapis lazuli blue, kermes red, orpiment yellow — some of them imported from the Mediterranean and as far as Afghanistan.

The book functioned less as a working theological text than as a liturgical object: it stood on the altar rather than in the monastic library; ordinary reading was done from working gospel-books. Opening the Chi-Rho page or a Gospel portrait was itself part of ritual.

Kept at Trinity College Library, Dublin, since 1661, two folios are turned each year for public display. It is the known summit of insular art — the joint Christian-Celtic tradition of the British Isles — and influenced Romanesque and Gothic illumination schools directly.