Both the scribe and the artist of this manuscript dated their work five times over a period of three years from 1476-1478. Twenty initials with figures and little scenes illustrate the codex; many show ornate foliate extensions, some are painted in gold and rich colours, others in a sophisticated so-called grisaille technique, which uses only grey hues. As the texts refer to the liturgical use for "the choir in Constance" , it is likely that the artisans came from the area surrounding Lake Constance.
A delightful and complex narrative unfurls in the margins of f. 87v and accompanies the feast of Nativity. In the initial H Mary kneels before her child, with ox and donkey carefully watching. Next to the letter, in the margin, colourful birds rejoice in the scene. To the above, angels hold a scroll with music for Gloria in excelsis mundi. As if it was a flower, petals emanate from the initial, spreading over a unicorn standing proudly on top of a mountain and looking over the world. The unicorn is the symbol of Christ and stands for the incarnation. Below in the meadows, shepherds are playing music next to their sheep, they join in what is happening by pointing in amazement towards heaven above. To the right, in the lower margin, a large city emerges. This must be Jerusalem, near Bethlehem, but charmingly envisaged as a south German walled city with gothic castle. Two figures (the Magi?) on the battlements point at the twinkling golden star on the highest tower. All is painted with purity, guileless simplicity and calm repose.
There are some similarities between the present manuscript and two others. One is in Basel, UB, B. IX. 36, dated 1479, where we encounter an – apparently unfinished – pen drawing. Interestingly, two of the initials on f. 121 of our Breviary are also outlined in pen drawing. The other related manuscript is in Zürich, Zentralbibliothek, C 131, dated 1480. The closest comparison, albeit less flamboyantly illustrated, is found in the Benedictional of Johannes of Venningen, bishop of Basel (1458-1479), in the collection William Alfred Westropp Foyle until 2000.