Heraldry on the first page of the Psalms text strongly suggests that this Psalter was commissioned by King Edward I for the marriage of his son Alphonso, to Margaret, daughter of Florent V, Count of Holland, which was to take place in 1284. Alphonso died before the wedding, however, and the decoration of the manuscript was left incomplete. Additions were made in the early 14th century, probably before 1316. The text of the Psalms is decorated fairly soberly, with illuminated initials to each Psalm and verse, and line-fillers. Accompanying each Psalm initial is a partial border, extending around a corner of the text area: each of these has a dragon head at one end, and foliage at the other. They provide the stage for a lion and a stag, each fighting a dragon, and a monkey riding on the back of a stork-like bird, with a demonic face on its backside.