14/10/2026
The Manuscript of the Week is RIA MS 24 P 25, Leabhar Chlainne Suibhne / The Book of the Mac Sweeneys. This 16th century manuscript contains an account of the 6th century dispute between St Colum Cille and St Finnian over the ownership of a copy a Latin Psalter, which led to the battle of Cúl Dreimhne. RIA MS 12 R 33, known as the Cathach, has been associated with this story. On page 81 of Leabhar Chlainne Suibhne, you can read the famous ‘copyright’ judgement made by King Diarmait Mac Cerbhaill: to every cow its calf and to every book its copy.
Read more about the manuscript and view the digital images, provided by Dublin Institute for Advanced Studies - DIAS Irish Script on Screen and copyright Royal Irish Academy (RIA): https://www.ria.ie/collections/manuscripts/irish-language-manuscripts/leabhar-chlainne-suibhne-the-book-of-the-mac-sweeneys/
The MS of the Week is on display in the Reading Room of the Library this week from 10.00-16.30, Monday-Friday, except for Wednesday, when the Library will be closed due to industrial action. No appointment or reader’s ticket is required to view the MS of the Week.