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The Max Planck Research Group Art and Knowledge in Pre-Modern Europe, directed by Sven Dupré, investigates how artists invented and appropriated knowledge, conceived and categorized knowledge, and transmitted and circulated knowledge in the visual and decorative arts in the pre-modern period. Started on October 2011, the research group is writing an epistemic history of art that focuses on the mediation of the circulation of knowledge within the artists' workshop and beyond as it travelled in other domains more familiar to historians of science, medicine and technology. An important focus is on artists' optical knowledge. Part of the Max Planck Institute of the History of Science, the research group collaborates with the Institute's library, directed by Urs Schoepflin, and its European Cultural Heritage Online (ECHO) initiative incl. its Art and Optics section, to make the documents presented in [Perspectiva+] available and open access.

We are thankful to the Bibliothèque de la Maison des Sciences de l'Homme of the Service Commun de la Documentation of the Strasbourg University for having provided the scans of Friedrich Risner's Opticae Thesavrvs. Alhazeni Arabis libri ſeptem, nunc primùm editi. Eivsdem liber De Crepvscvlis & Nubium Aſcenſionibus. Item Vittellonis Thvringopoloni libri X from their Bibliothèque numérique patrimoniale.

We are thankful to the Biblioteca Casanatense, Rome, for having allowed the scanning of Ms 1393 Alacensis Liber de aspectibus, et vocatur prospectiva. incipit de visione corporea, de luce, de oculis & Euclidis Perspectiva. De ponderibus Euclidis.