History of Bengali Calendar

Rahat Mahmud Polin

The Bengali calendar has not come suddenly. It has come to solve a special kind of problem. The Emperor of Delhi Akbar is the establisher of Bengali calendar. Then it was called as “Shan-E-Elahi”. And the reason of inception of the Bengali calendar was nothing else than the earning of tax facilities. There were two available calendars those days – Moon Month and Solar Year. But it was seen that the Moon Month was of 29 or 30 days and it makes the year of 354 days. On the contrary, the earth moves the terra once in 365 days which is recognized as a Solar Year.

At the time of Emperor Akbar the tax was taken according to the Moon Month.  As the Moon Year was less than the Solar Year for 11 days so the farmers were in trouble much. To solve this problem, he appointed the Astronologist and scientist Amir Fatullah Shiraji from Iran.  This great scientist made similarity with the available Iranian calendar of Solar Year and the regular Solar Year to implement a new calendar named as “Shan –E-Elahi” or “Fosholi Shan”. Its moderated form is the present Bengali Calendar. Though it was in effect since the 11 March of 1584 but it had been counted after starting of the rule of Emperor  Akbar. And the date was 5th November of 1556.

And the name of that time’s months was not like as present. The names were as follows-

  1. Kawardin
  2. Ardi
  3. Khordad
  4. Teer
  5. Amardaad
  6. Shahriar
  7. Vihishu
  8. Abaan
  9. Azaar
  10. Dey
  11. Bahman
  12. Ishkandar Miz

The first day of “Shan-E-Elahi” was known as “Tarikh-E-Elahi”. This day was observed with special prestige and significant programs. The moderate date of “Tarik-E-Elahi” is the present “Pahela Boisakh”. That’s why, the emperor Akbar is thinker to the establisher of Bengali Year.

Later the names of that month become in present name. The name of the Bengali months has been fixed according to the rotation of the moon with the position of the particular stars. This was taken from the astronomies book of “Shurjo Shiddhanto”. The name of the Bengali months and their origin-

  • Boishak- According to the star Bishakha
  • Joistho- According to the star Joistha
  • Ashar- According to the star Uttarsha
  • Shrabon- According to the star Shrabona
  • Vadro- According to the star Purbavadrapad
  • Asshin- According to the star Osshini
  • Kartik- According to the star Krittika
  • Augrahan- According to the star Agrahoine
  • Powsh- According to the star Pussha
  • Magh- According to the star Motha
  • Falgun- According to the star Choitra

At the regime of Emperor Akbar there were 31 different names for the different 31 days. It was not easy to remember all the names. That’s why, the grandson of Emperor akbar, Emperor Shahjahan implemented the 7 days of week with the similarity of other days of the month.  The names of 7 days were also fixed depending on the planets. And they are-

  • Saturday- According to the name of planet Saturn
  • Sunday- According to the name of Sun
  • Monday- According to the name of Hindu God Shom
  • Tuesday- According to the name of planet Mars
  • Wednesday- According to the name of planet Mercury
  • Thursday- According to the name of planet Jupiter
  • Friday- According to the name of planet Venus

Later Dr. Muhammad Sohidullah led a committee to correct the Bengali Calendar in 1966. That committee recommend to some terms after finding the problems. The duration of Bengali Year is 365 days. Although the duration of Sun’s rotation is 364 days 5hour 48 minute 47 seconds, it was taken as a whole day.  AND TO RESOLVE THE TIME, There was the way of 29 days in the month of February in leap year. Exceptional is that year which numerical number is undividable with 4. To solve these, Dr. Muhammad Sohidullah’s committee proposed the followings-

  • The first 5 months e.g. Boisakh to Vadro will be for 31 days
  • The rest months e.g. Asshin to Chaitra will be for 30 days
  • Every 4 years after, 1 day will be added with the month Falgun and then it will be counted as 31 days.

The Bangla Academy Formally accepted these proposals but in the Indian West Bengal it was same as before.

Now a strange question may arise that the founder of Bengali Calendar was Emperor Akbar was started his rule since 1556. Now it is 2017. So now it should be observed as the Bengali year 461. But are we observing the year as 1423?

No. There is no mistake. The initial year was counted as 963 of Hizri calendar. Since then he counted the calendar as follows. And that’s the open secret.


Main Story
Writer Rahat Mahmud Polin
B.SC Engineer (Studying)
Mymensingh Engineering College

Translation by
Shah Mizanur Rahman
Textile Engineer
Daffodil International University

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