Rediscovering the very first Italian digital computer

Until recently, the ELEA 9003 by Olivetti and the CEP by the University of Pisa were considered the first digital computers built in Italy. The CEP was the final outcome of a project carried out from 1955 to 1961 by the University of Pisa with a substantial participation of Olivetti. Actually, this seven years long project delivered a first fully functional computer already in 1957: the MR. However, for a number of reasons, the relevance of MR has been overlooked by previous researchers that underestimated its accomplishments. This paper offers a revised introduction to the history of the CEP project and adds an original chapter, devoted to the MR. We also briefly present the experimental archeology project that rediscovered the MR. In particular, we highlight the benefits that a re building approach brings to the proper reconstruction and to the correct evaluation of historical events.