Because of the square script and the use of minuscule for a liturgical text, O'Sullivan suggested that they might have originated in central Ireland,[2] and Joseph Flahive dates them to around 780.
[3] They display a close stylistic affinity with the Faddan More Psalter discovered in 2006, almost miraculously, in a bog near Birr, which is also in the Irish midlands.
On page 265, however, there is an entry in a Carolingian minuscule that possibly dates back as far as the second half of the 9th century, apparently imitating the Irish script.
Although there is no clear evidence that it had anything to do with the donation of books by the Irish bishop Marcus and his nephew Móengal during the period between 849 and 872, the idea cannot be ruled out.
The same quality is evident in a carpet page (p. 6), another decorative initial (p. 7), and depictions of the Crucifixion (p. 266) and the Last Judgment (p. 267) at the end of the book.