This paper discusses the cross-disciplinary study of a richly illuminated thirteenthcentury manuscript (Fitzwilliam Museum, MS 36-1950), combining codicological, art historical,
and noninvasive technical analyses. Each of this psalter’s 294 pages is decorated with illuminations
including 28 full-page miniatures, 10 large historiated initials, 168 small miniatures, and a variety
of figural and ornamental motifs in the margins. The volume’s extensive and diverse decorative
program poses challenges to the attribution of its numerous illuminations as well as the amount of
analytical data needed to help clarify its method of production and to inform its long-term preservation. Needing to prioritize, the first phase of our investigation, whose results are discussed here,
focused on the full-page miniatures and the historiated initials. The analytical protocol employed a
cross-disciplinary methodology including paleographical, textual, historical, art historical, and codicological analyses, which were interpreted together with the results of photomicroscopy, infrared
imaging, visible and near-infrared reflectance spectroscopy, and X-ray fluorescence spectroscopy. Focused on 38 illuminations, this comprehensive investigation produced an extraordinary amount of
data, which had to be cross-referenced and analyzed in a comparative way. The preliminary results
of this extensive investigation have so far produced a much clearer picture about the structure and
authorship of the decoration, and they are presented here as an example of an integrated approach
to the study of illuminated manuscripts.