Book made of gold, mercury, cows and goats

An unprecedented opportunity to analyse the materials used to create an illustrated Medieval book reveals that its multiple creators used rare pigments and precious metals – and required the skins of an estimated 10 goats and seven cows.

The Messale Rosselli is a fourteenth century illustrated manuscript that originated in Avignon, France, and today is kept at the Biblioteca Nazionale Universitaria in Torino, Italy.

When curators at the university library opted to conduct a careful restoration of the lavishly decorated 425-leaf volume, a multi-disciplinary team of scientists led by Elisa Cala of Italy’s Università degli Studi del Piemonte Orientale took the opportunity to have a very close look at the pages, and the inks and pigments used on them.

The team used a variety of non-invasive techniques, including fibre optics reflectance spectroscopy (FORS), fluorimetry, XRF spectrometry, and optical microscopy.

The results provide a rare insight into both the way important books were made in the Medieval period, and how original artefacts, themselves the products of several hands, were altered as they passed into different ownerships over the ensuing centuries.

The Messale Rosselli was originally produced in Avignon for the Aragonese Cardinal Nicolas Rosselli (1314–1362). The text was done by a scribe known as Alamannus, and scholars have previously drawn a confident conclusion that the illustrations were overseen by an illuminator called Bernard de Toulouse.

The tome was completed in 1361.

In the years immediately after Roselli’s death, the book passed through the hands of two other clerics, each of whom had their coats-of-arms and other elements added. Much later, during the seventeenth century, it was confirmed to be in a Franciscan monastery in Pinerolo in northern Italy, from where it eventually passed into the Savoy ducal library in Torino before finding its final home in the university.

The investigations conducted by Cala and her colleagues reveal that the pages of the book are derived from cow and goat hides. This was despite – or, more likely, because – parchment made from sheep skin was both more abundant and cheaper.

“The absence of sheep is not unexpected due to the nature of the document, a missal, which is considered to be a more prestigious and personal object, and a manuscript usually made with the most precious material as it was to be used on the altar,” they write in the Journal of Archaeological Science: Reports.

“Even the best prepared sheep parchment was cheaper (and presumably considered inferior) to even the worst prepared calfskin parchment.”

The ink and pigments used to create the highly decorated manuscript came from a mixture of commonplace and highly exotic sources.

The browns, for instance, were made using iron-oxide rich red ochre. This, the researchers note, was “absolutely common” in artworks of the period.

“Nevertheless,” they add, “it is worth noting the availability of high quality ochres at Roussillon, less than 50 kilometres from Avignon.”

Similarly, red, white and orange inclusions were derived from different combinations of red and white lead – again echoing common practice.

The grey bits, though, were unusual. In manuscripts of the period, grey was often created through the mixture of white lead and black carbon. Such a combination was used in the Messale Rosselli – but not on every occasion. Some grey features, notably the helmets of soldiers, were found to have been created using silver, either in powdered or leaf-form.

The use of silver, however, was by no means the most extravagant application made by Bernard de Toulouse and his assistants. His 700 gold areas, for instance, were made of actual gold.

“Some features are made with gold shell, such as clothes of important characters and the beautiful interweaving on the background of several historiated initials,” the researchers write.

“Most of the gold features are made in leaf and particularly relevant is the fact that gilding was carried out using different preparations.”

The blues were equally exotic, derived from the extremely expensive mineral, lapis lazuli.

Cala and colleagues note: “There was only one known source, the mines of Badakshan (modern north-western Afghanistan), from which the stone after a long trip, through the harbours of the near-eastern Asia coast, reached Venice and eventually Europe.”

Some hues, in particular red and purple, were constructed in whole or part from the mineral cinnabar – a rare, scarlet and extremely toxic form of mercury.

It’s use was widespread during the Medieval period, doing nothing to preserve the good health of the monks who laboured daily in Europe’s scriptoria. 

To make purple, it was mixed with a pigment known in those days as brazilwood – a confusing term to modern eyes, because it was derived from a plant called Caesalpinia sappan, sometimes referred to as sappan wood, which is native to India.

The pigment had been widely traded across Europe since the twelfth century, so its appearance in the manuscript is not unusual, the researchers say.

(The term “brazilwood”, by the way, isn’t a reference to South America, but reflects the German descriptive term “brezel”, from which the world also gets the word “pretzel”.)

Over all, the researchers conclude, despite the expense and rarity of some of the elements used, the various original and later artists and scribes who laid creative hands on the Messale Rosselli did so using “raw materials in the geographic area around Avignon,” most of which were easily available.

The restoration of the precious missal was completed early in 2018 – the conservation work aided by information gleaned by Cala and colleagues. The result was unveiled by the university library in April.