The knowledge of Modern architects libraries is mainly based upon inventories and catalogues; if books might be identified in public collections it is exceptional to have in situ a collection with catalogues and notes that record the making as the use of it – which is the case of Carl Johan Cronstedt’s library in Sweden. Thanks to the important drawing collection at the Nationalmuseum in Stockholm, the name Cronstedt is worldwide known by historians of European Modern Architecture - even if often mixed with Tessin. What is much less well known are the man behind this collection and his library, with a thousand books still standing in the family’s manor. Various documents inform about the origins and the use of the collection, such as Carl Johan’s letter-drafts and sketch-books from his study-trip (1732-37), catalogues of the library, letters from his elder son’s study-trip (1770-73) and two unpublished manuscripts upon architecture and building technologies. This paper will mainly focus upon these two last documents, thanks to which Cronstedt’s readings and field studies can be tracked through a selective bibliography and a modern foot-note system. The analysis of these manuscripts leads to a better comprehension of the culture as the view upon building technologies and architecture in 18th century Sweden, Europe.
During the spring 1729, at the age of twenty, count Carl Johan Cronstedt (1709-1777) started his training in mechanics and building technologies under the supervision of the Swedish inventor Christopher Polhem at Stjärnsund. The following year he became assistant of the intendant Carl Hårleman (1700-1753), then mainly in charge of fulfilling the reconstruction of the Royal castle in Stockholm. In December 1731, when Hårleman left for Paris to recruit French crafts-men and collect new models for this palace, he brought Cronstedt with him. Four months later the master returned to Sweden with a group of French sculptors and painters, as Cronstedt remained in Paris until 1735 - when he pursued his study-trip to Italy before returning to Sweden in 1737. It was during this period that he started collection of architecture: drawings, engravings and books. At his return in Sweden Carl Johan served as Hårleman’s closest collaborator until 1753, when he succeeded him as superintendant and director of the Fine Arts academy (1753-67).
In the early 1770’s, when Carl Johan’s eldest son (Fredrik Adolf Ulrik, 1744-1829) fulfilled his architectural education in Paris and Rome, he states that he never saw any library as extensive as his father’s; which we know he had a very good knowledge of as he kept a catalogue with him to purchase new and missing volumes. Thus it seems that its scale was exceptional; in Paris F.A.U. met with contemporary architects such as Ange-Jacques Gabriel, Jacques-Germain Soufflot, Jean-Rudolph Perronet, Pierre-Louis Moreau-Desproux and Jean François Leroy. In Rome he also became a close friend of Pierre-Adrien Pâris.
An unbounded manuscript with about 240 pages entitled Mémoire sur l’architecture is mainly written in French. Although the text is divided into sixty seven chapters, by numbers in the upper corners of the sheets, it holds no summary. Most of the pages are covered with a neat hand-writing in brown ink; some pages also contain more neglected additions with black ink.
This volume is mainly composed by transcribed extracts providing from French readings. Through a foot-note system in the right margins the text refers to thirteen works held in the library, classified according to references in a catalogue from 1742 (letter, format and number). These main sources cover a period from the mid 16th century until the second half of the 18th century; beside Serlio’s Le cinque libri d’archittettura (Venice 1551) the text only refers to French and Swedish books. As for many 18th century architects, Perrault’s Vitruvius and Daviler’s Cours d’architecture seem to have been very central in his theoretical training. The library holds two editions of each of these titles - 1673 and 1681 and two of Daviler - 1720 and 1738. Along with numerous ink sketches, the manuscript contains twenty illustrations taken from Daviler (1720).
The manuscript opens with the definitions of “architecture” and “architect” (according to Perrault, Delorme and Mariette), succeeded by an unfinished history of buildings. Then follow explications of different materials – for example general information taken from Vitruvius, more specific instructions concerning Parisian stone species, a list of European marble (Referring to Daviler 1738, p. 249) and in Swedish the qualities of the local “grey-stone”. Amongst the sections about mortar, brick, glass and iron lay sheets with comparative lists: sizes and weights of French paper (from Ramès), church dimensions (French, Italian and Swedish), bridge arches (mainly Italian), weight of different nail-species; and an extract from Loriot Mémoires sur une découverte dans l’art de bâtir à Paris (1774). The subsequent chapters count extensive instructions (texts, sketches and charts) about foundations, bridges, locks, walls, vaults, cellars and terraces; furthermore it deals with observations regarding the cutting, selection and use of wood. This last section also include two essays in Swedish - concerning timber, proportions of roofs and a transcription of count Espie’s invention of flat vaults in Toulouse (Espié 1754). Prior to Gautier’s instructions about water evacuations and road constructions is a presentation of urban rules, planning systems for public and religious buildings. Follows, with more or less details, a presentation about how to plan and decorate private houses – including a comprehensive outline of various heating systems. This section is succeeded by six chapters about garden designs and water supplies (fountains, wells, cisterns etc.). Only four incomplete sections deal with the proportions and the elements of architecture – thus this manuscript do not include any presentation of the Greek and Roman orders. Meanwhile the two last chapters display machines and instruments (ink illustrations and shorter texts).
The spine of another, bounded, manuscript bears a Swedish title: C.J. Cronstedts egenhändiga anteckningar om byggnadsteknik (C.J. Cronstedt’s handwritten notes upon building technology). This volume is mainly written in Swedish and organized as a register that seems to have been filled in during a longer period (about 300 pages). The lower part of the sheets are cut like a register, divided into eight thematic sections from A to H. Dealing with the same themes as the Mémoires, but often displayed in a different order, this version is more comprehensive and ambitious. The text is composed of shorter extracts from French readings translated into Swedish but also including information from essays published by the Swedish Royal Academy of Science; as Cronstedts personal field observations (Sweden, France, Italy) and professional experiences; it is illustrated with numerous explanative sketches.
The first chapter holds three bibliographies: a list of thirteen titles which the text refers to with help of a foot-note system in the right margins (A-L) and two more extensive lists of ancient and modern works that he suggests any architect to read. The first bibliography counts ten French and three Swedish titles, the oldest edition dates from 1673 and the most recent from 1762. Seven of these references correspond to those mentioned above for his Mémoires sur l’architecture. Added are the first reprint of L’architecture générale de Vitruve réduite en abrégé par M. Perrault (1681) and Des principes de l’architecture par Félibien (1676). It also includes a Swedish handbook about the making of roof-tiles and wall-bricks (Wijnblad 1762) and an extract from a franco-swedish book about steel (Bazin and Swedenborg 1737). and essays published by the Swedish Royal academy of science (Svenska kungliga vetenskapsakademien, KVA). The text repeatedly refers to this last source, Cronstedt was elected member of the academy the year it was founded (1739) and he served it in a very efficient way all through his life: as president, treasurer and author of several essays.
The introductive chapter is divided into four sections dealing with the definitions of architecture, the progress of building since the beginnings, how to obtain a healthy room or building and a presentation of the mechanical principles; The following chapters are organized by themes: machines and instruments used for building; stone-quarries, materials and ovens, mason-works, wood, private houses, garden designs, public houses and mechanical works.
The last pages are a compilation of charts (prices of mirrors, calculations of French measures into Swedish measures, etc.) and glossary lists (academies, inventions, symbols, engravers, monuments, quantities of materials for different purposes, etc.). It also holds three transcriptions: Blondel’s Resolution des quatre principaux problems d’architecture with a tracing (oiled) paper showing an instrument used to describe the enflure of columns; and General Virgin’s working proposals for the construction of Sveaborg (1766), listing working-craft, time and cost for different tasks. The third transcription is an extract from N. Bergier Histoire des grands chemins de l’empire romain (1728).
Whereas there are no proof that Carl Johan did teach; as superintendant he showed a great interest for educating the Swedish youth. In several Memorials to the king he argues for the utility of the mechanical laboratory - started by Polhem and today part of Tekniskamuseet in Stockholm - as the need of not only lectures in Fine Arts but also in Architecture at the Swedish Academy of Fine Arts. Hence these manuscripts can be interpreted as part of a Swedish tradition to “collect” and update knowledge about architecture. In fact the Cronstedt library also holds a note-book with the initials C[arl] H[årleman] entitled Abregé d’architecture 1 Partie and the Royal Library in Stockholm keeps a compilation of handwritten notes. Composed by texts in several languages and by different hands it seems to provide from Hårleman’s studies. C.J. Cronstedt might have studied these documents before leaving for Paris. Through contacts with C.G. Tessin he may also have had access to several unpublished manuscripts by Nicodemus Tessin the younger.
As the famous Tessin-Cronström correspondence, this Swedish documentation gives an exceptional insight in the European (mainly France-Sweden) transfer of knowledge and professional networks in the fields of arts and architecture. During his stay in Paris, Carl Johan was trained in Claude III Audran’s workshop at the Luxembourg palace and Jean-Michel Chevotet oversaw his education, he also got practical training in stone-cutting and perspective. According to his letter-drafts he spent a lot of time reading everything he could find about architecture and several sketch-books testify that he undertook various field studies. He also met with other contemporary architects, artists, collectors and librarians. For instance he had a close connection with Dom Montfaucon, was elected member of the Société des Arts et Sciences and he relays two visits at the Royal library. He doubtlessly even obtained access to private libraries and collections in the French capital, for example a loose sheet in the Mémoires sur l’architecture displays a transcription of a manuscrit chez Vigny (Pierre Vigné de Vigny). Alongside some more extensive notes in French (such as Extrait des entretiens sur les vies et ovrages des plus exclentes peintres anciennes et modernes par Félibien and Traité de la coupe des pierres by de La Rue), Cronstedt’s library holds three version of Antoine Desgodets unpublished Traité des ordres and one transcription of Desgodets Traité du toisé (Rollenhagen 2011 a). Foremost a compilation of practical instructions, the Mémoires sur l’architecture might thus have been begun as part of Carl Johan’s theoretical education in Paris; a note-book from readings and field studies, progressively updated with more recent information.
Meanwhile the title of the manuscript-repertoire bears the name of Carl Johan it seems mainly to have been written by his first born son F.A.U. Cronstedt. For example an addition written with black ink, is dated from 1780 - three years after Carl Johan’s death, and the text about garden designs seems to be by two hands (father and son?) – the first with lighter brownish ink refers to Daviler and Blondel – as the second section, written with darker ink, refers to L’art de former les jardins modernes ou l’art des jardin[s] anglois, 1771 and is illustrated by the plan of Richard Grenville Lord Temple’s house and garden of Stow in Buckinghamshire (from this book) complemented by a handwritten detailed legend in French. In the letters from his study-trip, F.A.U. shows a great esteem for the English garden designs and repeats his desire to go and see Chambers in London. In another letter F.A.U. explains how he copied drawings of the church in Dijon, and the church presentation (one page) is a comparative study of the cathedrals in Dijon and Paris; the manuscript also contains remarks as comparative sketches of Parisian building sites from the early 1770’s: such as the Neuilly bridge, Sainte-Geneviève, la Madeleine. Moreover explanations of the new opera house in Paris at the Palais Royal and the theater in Versailles - illustrated with ink sketches of technical details- are based upon field studies. Although Carl Johan does not mention Jacques-Germain Soufflot in his letter-drafts, they probably met in Rome, where he arrived in November 1735 with recommendation letters to the French ambassador (from J. Campredon) and to the director of the French academy (from the duke of Antin). Thirty-five years later, F.A.U. tells his father how this architect very generously showed him his ongoing church construction (Sainte-Geneviève), often invited him for dinner and that together they did visit the then ongoing building site of Jean-Rudolphe Perronet’s Neuilly bridge. During Cronstedt the youngers stay in Paris (On October 27 1772) Perronet was elected member of the Swedish Royal academy of science, Carl Johan was probably involved in the examination of his candidature (Sottiau 2007; Rollenhagen 2011b). Previously, in August 1771, F.A.U. Cronstedt had been admitted in the French royal academy of architecture (Chevotet, Leroy and Moreau were spokesmen for his candidature). During his stay in Paris he also presented the father’s rationalized wooden-stove at the French royal academy of science.
Finally translating information about Parisian materials into Swedish might surprise – how to make use of it in Sweden? The idea may have been to turn it available for craftsmen with knowledge of similar local materials. For example the second manuscript features Swedish suggestions for wooden roofs (bark and plank) and explains where to find Swedish slate as how to extract and use this stone. From other sources we know that Cronstedt often preceded in a very experimental and practical way, searching to develop and find new local materials adapted to Swedish needs (Cronstedt 1741). In fact these manuscripts often focus upon how to choose, test and prepare materials; they also include receipts for mosaics or concrete (Rome) and how to mould houses (Falun). Meanwhile both manuscripts exclude the classical orders and urban restrictions, classified according to subject areas they reveal the main concerns for a Modern architect-engineer: from the aesthetical aspects of architecture (interior planning and decoration), through technical issues (heating systems, water supplies and fire-safe materials), to a broader interest for urban infrastructures (town-planning, locks and water). Nevertheless it is difficult to deduce if these documents were composed for a private or a public purpose. If the first manuscript seems to have been conceived as a note-book, the second could as well be interpreted as a preparation of a hand-book for Swedish students in architecture and engineering - in fact the organization is close to the first publication of this kind in Sweden (König 1752).
Cronstedt, C.J., 1740, ”Observation om takstolars upsättiande på trädbygningar” in KVA’s handlingar, p. 448-450
Cronstedt, C.J., 1741 (1755) Tal om sten-hus (speach about stone-houses), Stockholm: Salvius.
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Gallet, M., 1995, Les architectes parisiens du XVIIIe siècle, dictionnaire biographique et critique, Paris : Mengès.
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Rollenhagen Tilly, L., 2011, ”Ur Carl Johan Cronstedts bibliotek. Fyra opublicerade kopior av Antoine Desgodets lektioner”, in Konsthistorisk tidskrift/Journal of Art History vol. 80:4.
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Sottiau, E, 2007, Les réseaux de relations d’un homme de science au siècle des Lumières : Jean-Rodolphe Perronet (1708-1794), Université de Marne la Vallée.
Tessin, N., Bjurström, P. and Snickare, M., (1712) 2000 Catalogue du cabinet des beaux-arts, Stockholm : Nationalmuseum
Tessin, N., Waddy, P. (dir.), (1717) 2002, Traictè dela decoration interieure, Stockholm: Nationalmuseum and Arkitekturmuseet.
Wijnblad, C., 1762, Afhandling om mur- och tak-tegelbruks inrättande, Stockholm: Hesselberg.
 Nationalmuseum in Stockholm holds two extensive collections of (French) architectural drawings from the modern times, the Tessin-Harleman collection (THC) and the Cronstedt collection (CC).
 Apart three notebooks with letter-drafts from C.J. Cronstedts study-trip (Riksarkivet E 3447), these documents are kept in the Fullerö library. Three ongoing research projects concern this documentation: a bibliography about C.J. Cronstedt (2012), a commented transcription of the note-books (2013) and a catalogue raisonnée of the library (2013).
 Three note-books at Tekniskamuseet (Stockholm) reveal the content of this instruction.
 A bounded volume in the library holds letters written by F.AU. Cronstedt to his father, mother and sisters during his stay in Europe.
 He bought both volumes of the first edition only nine days after his arrival in Paris (for 25 livres).
 The library holds several catalogues and lists with books to purchase.
 The volume in the library provides from Félibien: André Félibien’s ex-libris and Jean François Félibien’s signature.
The two extensive bibliographies also include: Chambray Parallèle de l’architecture antique et de la moderne (1704), Alberti Traité de l’architecture, Palladio Architecture (1726), Scamozzi Œuvres d’architecture (1736), Fontana L’architecture, Fischer L’architecture, Bibiana, L’architecture, Pezzo La perspective de peintres et des architectes (1723), Jones Traité d’architecture, Le Blond d’Argenville La théorie du jardinage (1747), Le Clerc Traité de l’architecture (1714), Courtonne Traité de perspective pratique, avec ces remarques sur l’architecture, Cordemoy Architecture (1714), De la Rue Traité de la coupe des pierres (1738), Derand L’architecture des voûtes (1743), Frezier La théorie & la pratique de la coupe des pierre (1754), Blanchard Traité de la coupe des bois (1729), Mésange Traité de charpenterie et des bois de toutte espèce avec un tarif général des bois, Potin Détail des ouvrages de Menuiserie and Laugier Essai sur l’architecture as Delalond’s comment upon this text.
 The fortification of Sveaborg in Finland was built in the mid-18th century under the supervision of Carl Johan’s second cousin, Augustin Eherenswärd.
 Kungliga Biblioteket, S 33.
 Due to his father’s economical situation and his own health problems he had to abandon this project.
 Riksarkivet, E 3447.