Who proposed 365 days a year and when?

The ancient Egyptian solar calendar is considered to be the first calendar to divide a year into 365 days.

As early as 6000 years ago, the ancient Egyptians created the world-famous "solar calendar" according to the fluctuation of the Nile.

They found that whenever Sirius appeared before sunrise, the Nile began to flood, so the ancient Egyptians set this day as the first day of the year. When Sirius appeared in the same position the next year, it happened to be 365 days, that is, a year.

A year is divided into three seasons, namely flood season, sowing season and harvest season. Each season is divided into four months, with 30 days in each month, and 5 days are added at the end of the year as a festival to worship the gods.

The Gregorian calendar we use today is derived from this calendar.

Extended data

Development history

During the long-term use of the solar calendar, the ancient Egyptians gradually realized that there was a difference every four years. In 238 BC, Egyptian Pharaoh Ptolemy III ordered an increase of one day every four years to correct this inaccurate mistake.

In 59 BC, Julius Caesar was elected consul of Rome, and hired an Egyptian astronomer, Mr. Sinis, to revise the chaotic ancient Roman calendar according to the Egyptian solar calendar.

The revised Roman calendar stipulates that there are 12 months in a year and 365 days and 1/4 days in a year. For the convenience of calculation, every three years will be divided into 365 days in a normal year and 366 days in a leap year from next year. 1, 3, 5, 7, 9, 1 1 month is the big month, with 3 1 day per month. 4, 6, 8, 10 and 12 are abortions, with 30 days per month. February is very special, with 29 days in a normal year and 30 days in a leap year.

When Caesar's nephew Octavian ruled Rome, he was born in August, so he took 1 day from February and added it to August, making August a big month, naming August Augustus after his own title, and swapping all months after August.

After this change, 1, 3, 5, 7, 8, 10, 12 months are big months, and each month is 3 1 day. April, June, September,165438+1October are abortion months, with 30 days per month. February is still a special month, with 28 days in a normal year and 29 days in a leap year.

1582, 1 In March, Pope Gregory XIII stipulated that any year whose century number is not divisible by 4 cannot be counted as a leap year, and it is still regarded as a normal year (for example, 1600 can be divisible by 4, which is a leap year, 1700) According to this regulation, there are 97 leap years in 400 years, which makes up for the error of 0.0078 days and improves the accuracy of the calendar.

The calendar after this reform is called "Gregorian calendar", and this new calendar was immediately adopted by Italy, Spain, France and other Catholic countries. Since then, a number of European countries, such as the Netherlands, Germany and Britain, have successively accepted the Gregorian calendar. Gregorian calendar has become a universal calendar all over the world, referred to as Gregorian calendar or Gregorian calendar.

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