The calendar which was used in the western world before the present-day Gregorian calendar. The Julian calendar differed in having all multiple-of-4 years as leap years
The solar calendar introduced by Julius Caesar in Rome in 46 , having a year of 12 months and 365 days and a leap year of 366 days every fourth year. It was eventually replaced by the Gregorian calendar. See table at calendar. the calendar introduced by Julius Caesar in Rome in 46 BC, that fixed the normal year at 365 days. The Gregorian calendar, the usual calendar used in western countries in modern times, is based on the Julian calendar
by Julius Caesar and slightly modified by Augustus, establishing the 12-month year of 365 days with each 4th year having 366 days and the months having 31 or 30 days except for February