Manuscript written in Ireland, probably for Down Cathedral in Downpatrick. Lawlor has dated the work as probably of the 13th or early 14th century based on palaeographic evidence. Henry and Marsh-Micheli have suggested the work could also be attributed to the 12th century based on the decoration.

This manuscript is a missal of the English (pre-Sarum) type introduced into Ireland from the later 12th century, with a few archaic, possibly local, features. The missal appears to have been copied from an Irish exemplar as suggested by scribal misinterpretations of the characteristic Insular abbreviations for 'autem' and 'enim'.

The text is incomplete and not bound in its original order. The manuscript is written in a later Irish insular minuscule hand. Lawlor notes that there is a difference in the character of the script between the Sanctorale and the Canon, but that this is perhaps not sufficient to suggest a change of hand. The work is divided into four distinct parts, and the number of lines of writing varies in each part.

The contents are as follows:

Temporale, folios 1r-76v.

Sanctorale, folios 77r-112v.

Canon, folios 113r-117v.

Missae Votivae, folios 118r-135v.

Lawlor suspects that this missal is an excerpt from a larger book, due to lacunae at the beginning of the Temporale and at the end of the volume. The Common of the Saints is also not present despite many implied references to it throughout the rest of the work.

Lawlor concludes that the original order may have been:

(i) Canon

(ii) Missae Votivae

(iii) [Common of Saints - missing]

(iv) Temporale

(v) Sanctorale

The decoration consists of initials of the ribbon and wire type, some ending in animal heads or delicate foliage patterns. The ribbon capitals occasionally include a beast-and-snake motif. The colours used are mauve purple, orange red, yellow, and light blue.

There are frequent annotations and inscriptions by later hands from the 14th to the 17th centuries throughout the work, most notably on the following folios: 9r, 20v, 28v, 31r, 37v, 38v, 41v, 39v, 40r, 55v (James Henrie), 56r (Maister James S Sym[on?] chalmer[s?] is my name James chalm[ers?]), 62v (Symond Chalmer, Henr[ie] [ar?]not), 63r, 63v, 70r, 84v, 85r, 92r, 104v, 111v, 112v (D[ominus] SINCLAIR OF ROISLING), 132r.

Quire signatures are occasionally visible in the form of lower case letters in the upper or lower corners of the rectos. Most have, however, been cropped.

The foliation of the is probably of the late 16th or early 17th century.