Il calendario gregoriano ideato da Luigi Lilio. Niccolò Copernico e le errate affermazioni di Galileo Galilei

During the 16th century, the disagreement between the dates of the Julian calendar, which had been in use since 46 BC, and the vernal equinox necessitated a correction to the computational rules used to regulate the flow of time. Luigi Lilio, using imprecise astronomical data contained in “The Alfonsine Tables”, was able to elaborate a calendar that has stood the test of time: the Gregorian calendar. In a famous letter written by Galileo Galilei to the Grand Duchess of Tuscany Cristina of Lorraine, he states that Copernicus had been summoned to Rome from far away Germany in order to participate in the reform work. Galileo Galilei, to protect himself from controversy with Church regarding his discovery of the heliocentric system, states: “with the new Copernicus’s doctrine not only has the calendar been regulated”. This misstatement, over the centuries, has contributed to generating confusion. In this article it is discussed that Copernicus’ calculations were not used by Luigi Lilio for the reform