Translated as ‘Book of Hymns’, this is the earliest manuscript in the Library containing a substantial amount of Irish. It contains devotional hymns in both Latin and Irish, used in the services of the early Irish church. Typically called a ‘service book’, the manuscript is one of the few survivors of its kind. It came to Trinity in 1661 from the library of Archbishop James Ussher, one of the Library’s most important benefactors.