A leap year has 366 days instead of 365. It occurs only in the calendars of reckoning based on the circulation of the Earth around the Sun or reckoning combined (Moon and Sun). It aims to enable the adjustment of the calendar year to the tropical year.
Every 4 years we add one day in February as a true year is not exactly 365 days, but 365.25.
However, added day in February it was not 29 days but added between 23 and 24 February. It has to do with the practice of ancient Rome, where since the time of Caesar’s leap day was introduced by repeating February 24 (the so-called. Bissextilis).
However, in the Jewish calendar leap year has an additional, thirteenth month. It is added every 3 or 2 years to align the solar cycle of the moon.
The first time leap years introduced in 238 years BC, when Egypt began to include an extra day every four years. In the year 45 BC Decree of Julius Caesar introduced the same question in Rome (hence the term Julian calendar). Extra day gained shortest month – February. The error of this reckoning is 1 hour at 128 years.
It is now widely used question in accordance with the Gregorian calendar, introduced in 1582 with the Bull of Pope Gregory XIII, in the leap year (number) satisfies the following conditions: it is divisible by 4, except for years ending in “00″, which are not divisible by 400.
February has 28 or 29 days. However, several times it happened that this month had 30 days. Such situations, however, had only a local character.
In 1712 years in Sweden, due to the resignation of the passage through the country to the Gregorian calendar and compensation arising from the attempt to change the calendar, the difference in the reckoning of time, February had 30 days . The reform of the calendar also included a subsidiary of Sweden, Finland, but the Swedish possessions in the German countries, which – like the rest of the Protestant countries – adopted the Gregorian calendar in 1700.
In the Soviet Union twice in February had 30 days. This took place between 1930 and 1931 was associated with the introduction in the country in 1929, a new, revolutionary calendar, according to which each month this February and lasted 30 days. In 1932, resigned in part from a different calculation of time and returned to the length of months, which is used in the Gregorian calendar.
It is believed that leap years are unlucky – according to ancient beliefs, they are not indicated in this year move, construction of homes and marriages.
Leap year brings supposedly incurable illness, financial problems and military conflicts.
A mere 29 February is more than unlucky Friday 13. In ancient Rome, then avoided even leaving the house!