Conservation of Medieval Manuscripts – Maurits Sabbe Library KU Leuven. Online Expo


The results of the study and conservation treatment of seven manuscripts of the Maurits Sabbe Library collection are documented in the focus presentation. The selection of conserved manuscripts are from 26th of June until 4th of October 2019 on display at the entrance lobby of the Maurits Sabbe Library, Charles Deberiotstraat 26. Detailed descriptions and photographs from the manuscript conservation treatment support the showcase presentation. The focus exhibition is supplementary available at the on-line exhibition platform of KU Leuven Libraries: Conservation of Medieval Manuscripts.

The Project is supported by the Fund Baillet Latour of the King Baudouin Foundation

Checklist for the digitisation of manuscripts


The Checklist for the digitisation of manuscripts is a tool to support safe digitisation of manuscripts in heritage collections. The instrument aims to give guidance to conservator-restorers, librarians, collection-care and digitisation professionals. A Dutch version of this essay was first published on the Metamorfoze website in 2016. Ilse Korthagen, junior conservator-restorer of manuscripts at the Book Heritage Lab – KU Leuven realized with the team of authors an updated version. The English version 2.0 can be downloaded.

Medieval manuscripts represent a unique part of our cultural heritage. It comes as no surprise then that libraries are keen to make these manuscripts – including the masterpieces among them – digitally available. Often in this process, however, too little attention is devoted to the material properties of the objects and the risks to which they are exposed while the manuscripts are being digitised. The role of the conservator-restorer in this process is not always obvious, though they have command of a relevant body of knowledge.

In manuscripts, value can be attributed both to the content and to the manuscript as a material object. The value of the content is largely transferable to the digital copy, but that of the material object is much less or not at all transferable. It is the responsibility of the conservator-restorer to ensure that the value of the physical object is recognised and neither diminished nor altered during the digitisation process. With the Checklist for the digitisation of manuscripts an aid is introduced that aims to reduce the risk of damage during handling in the process of digitisation and thus preserve the value of the object as much as possible.

The essay focusses on examples in Dutch and Belgian (Flemish) collections, although the methodology can be applied to any manuscript collection in heritage repositories.

The Abbey of Saint Pieter and Paul of Dendermonde is giving the Symphonia Codex by Hildegard von Bingen (12th century) in repository to the Maurits Sabbe Library, KU Leuven


In August 2017, the 12 century manuscript of Hildegard von Bingen’s Symphonia Harmoniae Caelestium Revelationum ( Codex 9 of Dendermonde) came to Leuven. The codex has been trusted by Abbot Gerard Van Malderen of the Abbey of Saint Pieters and Paul of Dendermonde to the collection of the Maurits Sabbe Library at the Faculty of Theology and Religious Studies. The Codex will be stored in the climate-controlled and secure Precosia room where it will be examined in the Book Heritage Lab, in close collaboration with the Imagine Lab and the department of Musicology in the Faculty of Arts.

In addition to the well-known Symphonia, a corpus of almost fifty-eight musical works, it contains three other important texts of Hildegard and her friend Elzabeth of Schonau.  dated to 1174/75.   Hildegard von Bingen (1098-1179) was a prominent German abbess, theologian, mystic, and composer. She wrote the Symphonia in the fifties and sixties of the 12th century in the Rupertsberg convent. The manuscript includes some sixty unison songs dedicated to the Father, the Son, the Virgin Mary, Saint Ursula, the Widows, and the Innocents, among others. Hildegard von Bingen composed the songs for liturgical use, organised them thematically, and called the whole Symphonia Harmoniae Caelestium Revelationum (‘Symphony of the Harmony of Celestial Revelations’, ed.). Only two original copies of this Symphonia have been preserved.

Around 1174, Hildegard von Bingen sent a copy of her Symphonia to the Cistercian Abbey of Villers in Brabant. Later, the manuscript entered the library of Benedictine Abbey of Affligem and was kept since the 19th century in St. Peter and Paul Abbey in Dendermonde.

No medieval composer has fascinated scientists, the general public, and religious communities as much as Hildegard von Bingen. The liturgical songs in her Symphonia have become part of the repertoires of classical and modern ensembles as well as those of religious congregations.

A digital version of the Symphonia Codex can be consulted in the IDEM database:

Listen to the Symphonia performed by Psallentes


The Conservation of the Charters of the Old University of Leuven

The KU Leuven Charter Project (2018-2021) is a multidisciplinary project of conservation, digitalization and valorization of the charters collection of the Old Leuven University (1425-1797). The Charter collection is kept in the University Archives and is since 2013 recognized as World Heritage by UNESCO through the inscription of the archive of Leuven Old University in the Documentary Heritage Register. The collection contains about 425 documents composed of 375 single pages and 68 quires, including papal bulls and various privileges and official administrative documents from aristocracy, cities etc. The project started in 2018 and involves a team of conservation, archive and digitalization specialists of different units of the university: the Book Heritage Lab, Expertise Center for Book & Heritage ( Faculty of Theology & Religious StudiesFaculty of Arts, Illuminare, Center for the Study of Medieval Art), the University Archive, the Imaging Lab (UBD) and LIBIS.

KU Leuven Charter Project is funded by Fund Baillet Latour – King Baudouin Foundation. In 2025, KU Leuven will celebrate the 600 year anniversary of the foundation of the University (1425).  The Charter collection, kept in the University Archive, has an unique archival, historic and symbolic importance.

Conservation of a Notarial Deed ( 1471-1476) reused as book cover

During conservation treatment: a notarial deed (?) related to benefice dispute, 1471-1476, later reused as book cover for a register of revenue of the Arnold Trot College

A notarial deed (?) related to benefice dispute, 1471-1476, later reused as book cover for a register of revenue of the Arnold Trot College. The recycling of the deed as book cover resulted in holes, folds, stains and tears. The document was also damaged by water, mold and insects. The charter was strongly rolled and wrinkled with a deeply shrunk and hardened zone.  After a dry cleaning, the parchment was zone by zone relaxed with indirect humidity through a membrane (Porelle-Goretex). First the shrunk zone, then progressively to the full opening of the parchment. Between each step, the relaxed zone was dried between blotting papers with magnets and/or pressure. The tears and other fragile zones were consolidated with Japanese paper and methylcellulose.

Conservation of Wax Seals

Cleaning of the seal of inv. 43b: privilege by archduke Philip the Handsome regarding the conservators of the university privileges (French version), Brussels, 21 December 1500

Colored or uncolored beeswax seals have a large difference in dimensions, color and shape.  Seals’ waxes have a colouration in the mass due to dyes or pigments. Through transport, manipulation and mechanical stress in the past the fragile beeswax seals attached to the charters are in extremely fragile condition: dusted, broken, the surface often abraded and the attachment to the parchment or textile broken. During conservation treatment they are cleaned and the dust is removed with cotton swabs, fine brushes and demineralised water. Mending broken seals is done with Plexigum PQ611 (20%) in Shelsoll D40. Another technique for mending broken parts is to add thin Japanese paper and Methylcellulose (6 %) between the broken parts. The white paper fibers are slightly retouched. Missing parts of the seals are not reconstructed and small fragments of beeswax are kept for documentation and analyses. 

Conservation of the Silk Cords

The wax or lead seals of numerous charters are attached with monochrome or bicolored twined cords, most of them in silk. These cords composed of numerous fine threads are often in a fragile condition or broken. To conserve these textiles, they have to be manipulated with great care as natural aging and losses makes them extremely vulnerable.

Silk conservation, Inv. 125: bull “Provisionis nostre” by pope Gregory XI, confirming the condemnation by pope Pius V of the teachings of Michael Baius, Rome 29 January 1579. Detail of the end of the cord ending as a tassel with several types of threads and different thickness. The threads are Z spun.

Before conservation, the textile threads and cords are documented in great detail: the direction of the twining, number of turns in 10 mm, number of threads, thickness of the threads, thickness and dimension of the cord and the way the cord is attached to the charter. The condition report is mentioning the uneven areas, deformations, discoloration, broken fibers, surface dust, skin deposit, lacunas and wrinkles. After documentation, the cords are dry cleaned with a latex free sponge the stability of the dyes is tested, deformation softened and flattened. Broken treads are individually stabilized with new silk treads and reattached to reconstruct the damaged area of the cord.

Conservation of the damaged silk cord at the attachment with the lead seal of inv. 74b: bull “In praecelsa” with privilege by pope Gregory XIII, confirming and expanding the university’s right of nomination, Rome 1 March 1573 (new style).

Conservation of the lead bulls

The collection of the Old University has 30 Papal Bulls. These charters have round shaped lead seals (bulla) of ca. 40 mm diameter. On one side the heads of Saint Peter and Saint Paul are depicted. Each head is surrounded by a circle of dots, and the rim of the seal is surrounded by an additional ring of beads. The heads are separated by a cross. At the verso side the name of the issuing Pope is inscribed. The condition of the lead seals are stable and only some white deposit of lead white is present on the surface. During conservation they are cleaned with soft brushes and then covered with a thin layer of microcrystalline wax for further protection. 


KU Leuven Charter Project: Book Heritage Lab; University Archive; Imaging Lab; LIBIS; Illuminare

KU Leuven Team: Lieve Watteeuw; Marc Nelissen; Morgane Plateau; Gert Baetens/ Digitisation: Bruno Vandermeulen; Hendrik Hameeuw; Nele Gabriëls/ Transport: Marc Ronsmans/ LIBIS:Valérie Adriaens / External conservation specialists: Justine Marchal, IPARC (Wax); Joke Vandermeersch (Textile); Derek Biront ( Metal)

KU Leuven Charter Project is funded by Fund Baillet Latour – King Baudouin Foundation

The Breviary of Geraardbergen. 15th century illuminations and some extra pendrawings inspired by Reinaert de Vos

The Breviary of Geraardsbergen, a manuscript in the collection of the Benedictine Abbey of Maredsous, includes four richly decorated volumes.  Each volume has ca. two hundred parchment folios, bound in an early nintheenth century half-red morocco bookbinding. On the back of the bindings we find the titling in gold “Breviarium manuscriptum. Anno 1200”.  The inscription is completely misleading, the Breviary was made  for the St. Adrians Abbey of Geraardsbergen in the middle of the fifteenth century. In the early 19th century, when this titling on the newbinding was done, the approach in medieval manuscripts studies was in its very early stages and mistakes of a few centuries were not unusual. The right date is mentioned in the inscription on the first folio of volume 1, Monasterii sancti adriani gerardim, and by the two colofons with the dating 1449/1450 (in volumes three and four).  The scribe of this large work is Wilhelmus de Predio (or Praedio), and the manuscript was  commissioned by Abbot Nicaise de Frasne for the abbey of Grammont or Geraardsbergen. 

The manuscript is illuminated by several artist active in Gent and Bruges in the middle of the 15th century, and has lavishing penwork in the margins depicting scenes inspired by the story of Reinaert de Vos.  Together with the colleagues of the Royal Institute of Cultural Heritage, the Abbey in Maredsous and supported by the Fund Baillet-Latour from the Koning Bouwdewijn Stichting,  the manuscript will be conserved, digitized and studied in depth before returning to the Abbey of Maredsous in 2020.

Lieve Watteeuw, 24 June 2018


Khirbet Mird Papyri – Research and Conservation Project – Book Heritage Lab

Conservation & Rsearch of the Khirbet Mird Papyri 

The large groep of papyri in the Leuven University Library Collection comes from Khirbet Mird, a site in the neighborhood of Qumran, where a team of Leuven theologists-archaeologists under direction of professor De Langhe excavated them in 1950. These texts do not belong to the world-famous Qumran-findings dating from the start of our calendar, but are remnants of one or multiple monastic libraries and archives from the seventh or eighth century AD. When the excavation was finished, the papyri were divided between Leuven University (texts with the inventory number M.A.B. = Mission Archéologique Belge) and the Palestine Archaeological Museum (inventory numbers starting with P.A.M.) A part of the P.A.M. texts are currently kept in Leuven for research purposes. 


Documentation and analyses

In 2018 Lieve Watteeuw and the French conservator Eve Menei started the documentation and the conseration treatment of the collection, as the glass plates were never openened after the quick mounting in Jerusalem in the middle of last century. The condition of some of the fragments was very poor: dirt deposit, folded and occasionally consolidated with cellotape. Some of the glass plates were broken and fragments were unsave and “floating” between the two supports. After high resolution photography in collaboration with the Digital Lab ( condition images before treatment), a group 14 plates were  selected for the preliminary research on their material condition and stabilisation.


To define the composition of the ink, the Lab collaborated with the Royal Institute for Cultural Heritage in Brussels ( KIK-IRPA). The technique of MA-Xrf scanning was applied to reveal the composition of the writing inks on the papyrus.The analyses are carried out with non-invasive methods, by means of a macro XRF M6 Jetstream of Bruker, with a Rh-source, at 600 µA and 50 kV. The M6-software was used for both data collection and the following data processing (deconvolution of spectra, calculation of the “sum” spectrum and maximum pixel spectrum).Some of the fragments are written with carbon ink, other with iron gall ink.

Bibliography Khirbet Mird Papyri

Willy Clarysse, Inventory of the Khirbet Mird Papyri at the K.U.Leuven [ongepubliceerde catalogus], Leuven 1999.

Leuven database of Ancient Books (LDAB;

Emmanuel Tov, The Dead Sea Scrolls on microfiche : a comprehensive facsimile edition of the texts from the Judaean Desert, Leiden, 1993.

Joseph Van Haelst, “Cinq textes provenant de Khirbet Mird”, Ancient Society 22 (1991), p. 297-317.

Jospeh Van Haelst, Catalogue des papyrus littéraires juifs et chrétiens, Paris 1976.

Stéphane Verhelst, “Les fragments de Castellion (Kh. Mird) des Évangiles de Marc et de Jean (P84)”, Le Muséon 116, 1/2 (2003), p. 15-44.


A closer look to the Bible of Anjou Project

The 14th century Bible of Anjou is one of the treasures of the Maurits Sabbe Library of KU Leuven. The last years, a team of experts were contributing to the research of the illuminated Bible. More about the history and conservation of the Anjou Bible and the cultural and historical context, you can find in this illustrated document with abstracts of the publication: The Anjou Bible, Naples 1340. A Royal Manuscript Revealed  ( link: Bible of Anjou Abstract.

Left: Parchment repair on the edges with elegant overpainting. Right: Detail imaged with Hirox 3D Binocular, documenting paint layers en measurement of the hight profile


Rijmbijbel van Jacob van Maerlant – New research on the 13th century illuminations

Maerlant is one of the most important Middle Dutch authors during the Middle Ages. The 13th century Rijmbijbel ( Brussels, KBR 15001) is the oldest illustrated manuscript in the Dutch language.

Illumination on Fol. 76 v., detail: Elijah on the fiery chariot.

Dies ghi horet te voren lien, In dien tiden horic talen, Wilde god heliase up halen, Ende hi ginc doe in galgala, Ende heliseus volgede na, Bliif hier sprac hi du does wel…

The prophet Elijah is taken up to Heaven alive on a fiery chariot without horses. The chariot hovers in the upper half of the miniature. On the left is Eliseus, the close attendant and successor of Elijah, who is in prayer and receives the ermine mantle of Elijah. Eliseus asked Elijah if he could inherit a “double-portion” of his spirit. Elijah replied: “You asked a hard thing, but if you see me when I am taken away from you, your prayer will be answered; if you do not see me, your prayer will not be answered.”

In collaboration with the Manuscript Department of the Royal Library of Belgium and the conservation studio of the KBR, Lieve Watteeuw starts in February 2017 an integrated research on the material characteristics of the “Rijmbijbel of Jacob van Maerlant”. With scientific imaging (the Micro-dome, the Hirox 3D binocular) and through Xrf mapping the project will reveal detailed information on production characteristics of this important 13th century manuscript and support the conservation treatment. The research is in collaboration with the Imaging Lab – KU Leuven and the laboratories of the Royal Institute for Cultural Heritage.

Brussels, Royal Library, 17 Februari 2017


Looking closer to a French Book of Hours with the Hirox 3D Binocular

The Museum Mayer Van den Bergh in Antwerp has a rare late 15the century French Book of Hours in its collection. Before 1900 this Book of Hours ( around 1480-1490) entered the famous art collection of Fritz Mayer van den Bergh (1858-1901). The calendar of the manuscript is in accordance with those of the diocese of Paris ( Use of

Paris), with the presence of Sainte Genevieve, and on top the month of January, the inscription “Paris”. As the conservation condition of the manuscript was unstable, a research and conservation treatment of the manuscript was requested in 2016-2017. Examination under the Hirox 3D binocular could reveal in detail the extremely delicate execution of the illumination, but also the fragility and lacunas in the the paint layers. These details of damage of illumination are made visible under high maginifacation.

5 February 2017


The 18th century Library of Cardinal d’Alsace. Acknowledgement and Preservation of a new ‘Flemish Masterpiece’


The eighteenth-century Library Cardinal d’Alsace is in its entirety acknowledged as a Flemish ‘Masterpiece’. The Library, a collection of nearly 12,000 volumes, was compiled by Thomas-Philippe d’Alsace de Boussu et de Hénin-Liétard (1679-1759), archbishop of Mechelen. The collection waAlsace03s intended as a “public” library for the benefit of the clergy in Mechelen and consisted of about 9,400 titles covering all disciplines. Today the remarkable collection is carefully preserved in Flanders and put at the disposal of research teams on two locations: the Maurits Sabbe Library of the Catholic University of Leuven and the Municipal Archives of Mechelen. In 2016 more than 3,000 volumes of the Library Cardinal d’Alsace were preserved thanks to the support of the Fund Baillet Latour ( ). Alsace

The Library Cardinal d’Alsace is considered as a unique example of a religious-scientific collection from the eighteenth century, established on behalf of the secular clergy. Cardinal d’Alsace provided the collection with its semi-public character by making it available to the large number of priests, canons, seminary professors, and other members of the secular clergy in the “City-on-the-Dyle “. The collection was established in a professional manner and with a clear organizational system. It is the only religious-scientific library in Flanders which can be traced back to the period before the French Revolution, of which the content is known up to separate volume level and of which a significant part is preserved to date as a separate collection. The collection’s unique cultural-historical value is confirmed by its inclusion on the Flemish Masterpiece list and celebrated on 19th of December 2016.