Roman calendar
![Drawing of the fragmentary Fasti Antiates Maiores (ca. 60 BC), a Roman calendar from before the Julian reform, with the seventh and eighth months still named Quintilis (](/Images/godic/202501/30/Roman-calendar4807.png")
![The Fasti Praenestini.](/Images/godic/202501/30/Fasti_Praenestini_Massimo_n14807.jpg")
![A fragment of the Fasti Praenestini for the month of April (Aprilis), showing the nundinal letters on the left edge](/Images/godic/202501/30/Fasti_Praenestini_Massimo_n24807.jpg")
![Fragment of an imperial-age consular fasti, Museo Epigrafico, Rome](/Images/godic/202501/30/Kalender4807.jpg")
The Roman calendar changed its form several times between the founding of Rome and the fall of the Roman Empire. The common calendar widely used today is known as the Gregorian calendar and is a refinement of the Julian calendar where the average length of the year has been adjusted from 365.25 days to 365.2425 days (a 0.002% change).