The Romans
Leap years were first implemented in the Gregorian calendar in 1582.
The Romans by Emperor Julius Ceasar with the help of his astronomer,
The calendar used in Australia is the Gregorian Calendar, which divides the year into 365 days, and a Leap Year (of 366 days) in every year that is divisible by four. In the Gregorian Calendar, Leap Years do not occur in centenary years that are not divisible by 400, such as 1900 and 2100. The Gregorian Calendar was derived from the Julian Calendar in 1582. The Julian Calendar is not fixed to commence on the first of January, and has a leap year "every" fourth year.
It is the Gregorian calendar which we use today
In a Leap Year one day is added to the calendar - February 29.
No, odd-numbered years are never leap years in either the Gregorian calendar or the Julian calendar.
Julius Caesar introduced leap years when he reformed the Roman calendar in 46 BCE. His calendar, which is called the Julian calendar, was in use for almost 20 centuries. Beginning in 1582, it was eventually replaced by the Gregorian calendar, which is almost identical to the Julian calendar but is more accurate because it has fewer leap years.
Yes. If we did not insert the leap day during leap year, the calendar date of the equinoxes and solstices would change and eventually come at very different times in the calendar year. The whole purpose of Leap Year/Leap Day is to keep our calendar aligned with the equinoxes, solstices, and seasons in general.
2012
A leap year!
in February
The 2000 calendar will repeat in 2028. This was a leap year and leap year calendars generally repeat every 28 years.