The earliest illuminated manuscripts that have a definite or possible association with Wales are two gospel-books: Lichfield Gospels and Hereford Gospels. Art-historically the Lichfield Gospels may be placed somewhere between the Lindisfarne Gospels and the Book of Kells. The Hereford Gospels is a rare surviving example of a non-luxury gospel-book which primarily functioned as a lectionary. Each framed page is set out on a fairly grand scale consisting of an ornamental monogram comprising three letters followed by decorative geometric capitals. The form and layout of the decoration in both manuscripts is part of an Insular continuum dating back to the eighth century. There is evidence for the continuing use of Insular illuminated exemplars in Wales as late as the mid thirteenth century. The earliest version of the Welsh law book Llyfr Iorwerth includes some heavily cropped drawings including winged evangelist symbols, in the lower margins of three pages.

Gospel-books produced in Ireland, Britain and Insular centres on the Continent constitute an important phase in the history of medieval book design. These books were elaborately decorated and written in formal script, and were impressive witnesses to the sacred and authoritative nature of Christ's words and actions. Insular manuscripts display greater variety in their layouts, scripts and decorations than the Mediterranean counterparts which served as their immediate or ultimate exemplars. In Codex Usserianus Primus, projecting semi-circles on the corners and red dots surrounding the monogram are the only elements that presage later developments in Insular decoration. Although Kells' gospel text was copied carelessly, in one instance a page was written twice, aesthetic qualities of script and decoration appear to have been of the highest concern to those producing the book. The presence of more than 2,000 decorative motifs within the text, however, distinguishes Kells from other Insular gospel-books.