Over 2000 years ago, Roman General Julius Caesar introduced Leap Years into the Roman empire to replace exsiting Roman Calander. The new calendar named after General Julius Caesar is called Julian Calander which took effect in 45BC.

In Julian Calander, the rule of leap year is evenly divisible by four. The Julian Calander was used until the Gregorian calendar introduced by Pope Gregory XIII in 1582. The Gregorian calendar is the calendar we are using today and is accepted internationally as it is more accurate about the leap year. For more, read how the Gregorian calandar calculate leap years.