The Eadwine Psalter (Cambridge, Trinity College Library, MS R.17.1), previously known as the Canterbury Psalter, has been called the most ambitious manuscript produced in England in the twelfth century. It has also been called the most extensively decorated 12th-century English manuscript. It was written on calf vellum, and illustrated at Canterbury circa 1155-60, with additions circa 1160-70, and was kept at the Cathedral Priory of Christ Church, Canterbury through most of the Middle Ages. Its unusually large leaves measure approximately 460 x 330 mm.
It is a "trilingual, glossed psalterium triplex," containing
"a calendar, triple Metrical Psalms 90:15-95:2, canticles, two continuous commentaries, two prognostications, a marginal image of Halley's Comet (recorded in 1147), a diagrammatic representation of Christ Church's waterworks, and a full page visual memorialisation of Eadwine. At least 13 scribes appear to have been employed in the construction of this manuscript. Many of these scribes are part of a cohesive programme of matched, or near-matched, hands, making some sections difficult to attribute to one particular scribe" (http://www.le.ac.uk/english/em1060to1220/mss/EM.CTC.R.17.1.htm, accessed 02-16-2014).
The book contains five different versions of the text of the Psalms, three in Latin, one in Old English, and one in Anglo-Norman, with a prologue, a commentary, and a concluding prayer to each Psalm.
During the period of production of the Eadwin Psalter the Utrecht Psalter was in Canterbury, and its complex set of illustrations were copied and adapted for the project. The largest known cycle of prefatory biblical pictorial narrratives of the period was devised and appended as a pictorial preface, and every Psalm, prayer, and Canticle was embellished with fully illuminated initials as well as gold and silver minor initials. The portrait of the monk Eadwine as scribe on folio 283 verso of the Psalter has been called "perhaps the most famous portrait of its kind from medieval Europe." (Gibson et al, 178).
The manuscript was published in black & white facsimile by M. R. James as The Canterbury Psalter (London: Friends of Canterbury Cathedral, 1935). The best overall study of the manuscript is Gibson, Heslop & Pfaff (eds.) The Eadwine Psalter. Text, Image, and Monastic Culture in Twelfth Century Canterbury (1992). (In February 2014 I was pleased to acquire a beautiful copy of this rather splendid small folio volume for only $46.22.)