Severely damaged in a fire in 1731, this psalter was part of the collection of Robert Cotton which eventually became part of the British Library. It was made in Ireland, although where is not known for certain. An inscription, now lost, was supposed to have connected it to a person called Muiredach. The most well-known Muiredach was abbot of Monasterboice in the early 10th century, and usually the psalter's origin is placed there for that reason. Also, some of the decoration in it resembles carvings on the stone Cross of Muiredach at Monasterboice. The first letter of Psalm 51 is large and elaborately decorated, marking the second division of the psalter according to the Irish tradition. Several different systems of psalter divisions existed in the middle ages, the three-part system being distinctively associated with the irish. The ornament of the initial is in the style of late 9th and 10th century Irish book art, with fanciful, elongated animal's bodies forming the letter's shape. The interlace and fret patterns in the frame are rooted in earlier traditions of Irish decoration.