Difference Between Julian Calendar And Gregorian Calendar. It was this calendar which added one extra day in every four years (giving us our 'leap year') because it had been. The julian calendar is the name given to the revised roman calendar that was introduced by julius caesar (with the.
The julian and gregorian calendars have different leap year rules, with the gregorian calendar having a more complex rule to account for the drift caused by the julian calendarโs simpler rule. It was this calendar which added one extra day in every four years (giving us our ‘leap year’) because it had been.