Reliving history: the digital reconstruction of the convent of Santa Maria delle Grazie in Milan

Can we preserve cultural heritage and, consequently, the memory of the past? To answer this question, one should look at the digital revolution that the world has gone through in recent decades and analyse the complex and the dialectical relationship between cultural heritage and new technologies. Thanks to these, increasingly accurate reconstructions of archaeological sites and historical monuments are possible. The resulting digital replicas are fundamental to experience and understand cultural heritage in innovative ways: they have complex and dynamic relationships with the original objects. This research paper highlights the importance and the scientific validity of digital replicas aimed at understanding, enhancing and protecting cultural heritage. The study focuses on the virtual reconstruction of the constructive phases, from the mid-15th century to date, of one of the most emblematic Gothic-Renaissance buildings in the city of Milan (Italy): the convent of Santa Maria delle Grazie, famous worldwide for hosting Leonardo da Vinci's Last Supper painting. This site proved to be an ideal case study because of its troubled and little-known history that led to numerous changes over the centuries. Thanks to a methodological approach based on the analysis of the documentary sources and three-dimensional (3D) modelling, it was possible to outline the chronological succession of the convent transformations; the way in which these overlapped the pre-existing structures was described starting from the Renaissance harmonious and organic interventions, to finally reach 18th-19th centuries inhomogeneous and incompatible additions. Finally, the research was completed by mapping the 3D models based on the sources used and their different levels of accuracy. The 3D models have thus become a valid tool for checking and verifying the reconstruction hypotheses. Highlights: • The study focused on the virtual reconstruction of the convent of Santa Maria delle Grazie, one of the most emblematicGothic-Renaissance buildings in the city of Milan. • By combining data from documentary sources, architectural treatises, period photos and digital survey, the mainbuilding phases of the convent, from the 15th century to date, were digitally reconstructed. • The 3D models are enriched with information about the accuracy of the digital reconstruction, creating 3D databasesthat can be easily consulted and updated.