What did a Roman calendar look like?The Roman calendar used a system of months, and special days in each month. Some calendars were carved in marble or stone, but many were painted on walls for decoration.
Different geographical areas often held different gods in special esteem, and this led to regional variations in calendars. This doesn’t seem so strange when one considers that even within the US, Mardi Gras often appears only on Southern calendars, and Lincoln’s birthday sometimes does not.
In 45 B.C.E., Romans modified their method of marking time to keep it in phase with seasons, but not require intercalation of an extra month. They accomplished this with the Julian Calendar. Month lengths were extended to bring the calendar’s total to 365 days, making it truly solar. This change was accompanied by addition of an extra day every fourth year (after February 23rd) because of the almost six extra hours beyond 365 days in a tropical year.