Around the age of thirteen, Ton Koopman (born 1944) not only discovered the harpsichord, he also picked up his first ‘old’ book at a shop in his native city of Zwolle. Allured by the sight, touch and smell of a nineteenth-century edition of Molière's works, he purchased the volume and thus embarked upon a lifelong quest for old prints and manuscripts. Since that day, Koopman has collected nearly twenty thousand volumes. The fruits of this passion (or addiction, some would say) were recently acquired by the Orpheus Instituut in Ghent with the support of the Désiré Collen Foundation, the Flemish Authorities and the City of Ghent. This report offers a glimpse into the Koopman collection and the plans that are unfolding in connection with it.

Ton Koopman is globally acclaimed as an organist, harpsichordist and conductor. His period-instrument performances of seventeenth- and eighteenth-century music, both as a soloist and with the Amsterdam Baroque Orchestra and Choir, can be heard on well over two hundred discs, including complete recordings of Buxtehude's works and J. S. Bach's cantatas. Koopman has furthermore built up a reputation as music pedagogue and professor at the Koninklijk Conservatorium Den Haag and the Universiteit Leiden. As far back as 1985 he offered a survey of baroque performance practice in a book entitled Barokmuziek: Theorie en praktijk (Baroque Music: Theory and Practice). He also published critical editions of Handel's Messiah and organ concertos, and contributed several essays to the heated debate concerning the performance forces of Bach's vocal works (one or multiple singers per part).

Reflecting his artistic and scholarly pursuits, Koopman's collection has brought together around five thousand early printed editions and four hundred manuscripts, which date between the late fifteenth and the early twentieth century. Several items in this library are extremely rare, if not unique. The most notable example that has emerged from the collection in recent years is undoubtedly the variant version of Handel's soprano cantata ‘Tu fedel, tu costante’ (hwv171a). It is included in a manuscript that Koopman bought half a century ago, unaware of its supreme value as a Handelian source (see John H. Roberts, ‘Tu fedel? tu costante?: Two Versions of a Handel Cantata’, Händel-Jahrbuch 64 (2018), 207–236). Other treasures include sixteenth-century partbooks of Orlando di Lasso's Cantica sacra, lamentations and sacræ cantiones, which not only are preserved in their contemporary bindings but also contain further music added in manuscript. From the same period, the collection also contains early editions of madrigals by John Wilbye and motets by Melchior Vulpius. Noteworthy manuscripts for the later period are dance-master volumes from the Lullian era, an autograph of harpsichord music by Claude-Bénigne Balbastre, methods on harpsichord playing and composition in the hands of Jean-Joseph Boutmy and Pierre-Louis Pollio respectively, and sets of early instrumental parts for compositions by Corelli, Haydn, Wanhal and Mozart. The collection also includes numerous first editions signed by their authors, as well as exemplars originating from the libraries of, among others, Johann Christoph Friedrich Bach, Ernst Ludwig Gerber, Alfred Cortot and Alexandre Guilmant.

In addition to these historical materials, Koopman has also collected nearly ten thousand modern books and scores, a further thousand facsimile editions, nearly one hundred long-running series of journals and over four hundred microfilms of musical sources. Two elements make this corpus worth keeping together: first, its broad range of topics within the long eighteenth century; secondly, the fact of its being annotated extensively by Ton Koopman himself.

Although music is, understandably, the focal point of the collection, Koopman has also sought to inform himself about nearly every imaginable subject pertaining to the broader culture in the period for which he has such a predilection. Thus his interest in the vocal music of the Baroque is reflected in the significant number of theological and devotional books dealing with the various strands of Christianity of that time: Catholicism, Lutheranism, Calvinism, Pietism, Remonstrantism and so forth. Particular sections of the library cover choral and psalm singing, liturgical ritual, theological reflection, morality and personal devotion. Other sections cover the general history, theatre, fine arts and literature of Europe. The collection is particularly strong on the Low Countries and the German-speaking world, but there are books in at least nineteen different languages. Overall, the Koopman library offers a strikingly comprehensive view of the intellectual world of the long eighteenth century.

A particular feature is the wealth of material traces of the owner's reading practices that are left in the volumes. Koopman has the habit of maintaining lists of keywords referring to topics of interest he encountered while going through each book. Written onto separate slips of paper (in the case of the historical collection) or directly in the initial blank first pages (in the case of modern books and journals), these annotations add Koopman's own layer of reference points to existing printed indices (in modern books), or even provide unique entry points for a detailed exploration of a book's content.

The nature of Koopman's keywords varies enormously: they can comprise more or less generic terms that relate to a book as a whole (such as ‘temperament’ or ‘articulation’) or more specific subjects that are mentioned in the book and that a normal index might well also contain (‘minuet’, ‘polychorality’, ‘trumpet’). Crucially, they also include well-circumscribed topics that hold Koopman's interest or that for some other reason are not usually indexed as such. The ‘one-singer-per-part’ debate, for instance, is reflected in the keywords: Koopman has taken continuous note of textual and iconographical evidence supporting his conviction that multiple performers played or sang from single parts in Bach's time. Other keywords refer to choral and orchestral setups, the choice of continuo instruments, organ registration, tempo, pitch and so on, down to terms like ‘painted organ shutters’, ‘birds and music’, ‘boy soprano’ or ‘string thickness: violin’. The value of such annotations clearly lies in their heuristic power, transmuting more complex ideas or topics, which often do not appear verbatim in the text itself (and which cannot therefore be retrieved using Optical Character Recognition), into modern interpretative concepts.

Koopman's keywords thus hold a double interest. On one level, they continue to provide an extremely useful tool to performers and researchers, offering myriad thematic maps through the prints and manuscripts. On another level, they constitute the physical and legible sediment of one person's reading practices and way of ordering information. As such, they hold an interest in the larger context of the history of the book and of reading, precisely at the historical junction brought about by the current advancement of digital publishing and browsing.

Unfortunately, Koopman's lists of keywords have thus far been linked exclusively to individual books, rather than to a master index. Searches for information about specific topics through the collection have relied on Koopman's own recollections of which books covered which topics. Once identified, the lists of keywords then provided a shortcut to access the relevant pages in each individual book. One of the current steps is to transcribe, structure and unite these keywords into a digital index that not only allows fast searches through the topics treated by books in the collection, but can also function as a set of bookmarks in digitized versions of Koopman's books.

Far from expressing a desire to turn Koopman's library into an old-book museum or a documentation centre, the new Resounding Libraries research group that has recently been established at the Orpheus Instituut is developing digital strategies not just in order to disclose the contents of the thousands of scores and books in the collection, but also to help advance the historically informed performance of music from the long eighteenth century. Naturally, a number of more basic tasks are first being undertaken in order to turn Koopman's private collection into a user-friendly research library. In July 2020 all books were relocated to a remodelled building in the heart of Ghent. The library's new home reflects its historical contents very well, being the former coach house (‘Koetshuis’) of the Hôtel d'Hane-Steenhuyse, a mid-eighteenth-century city palace that once hosted visits by, among others, Tsar Alexander I, John Adams and Louis XVIII. At present a new online catalogue is being developed in association with Ghent University's CaGeWeB network (Catalogus van Gentse Wetenschappelijke Bibliotheken) (see www.cageweb.be). The new records enrich a former catalogue with a wealth of new metadata and even links to digitized exemplars of the works that are already available online elsewhere. As soon as the global public-health situation allows it, the library will be officially inaugurated with a colloquium, ‘Performing by the Book? Artist-Researchers’ Negotiations Between Text and Act’. It aims to be fully functional and open to visiting researchers in the course of 2021.