Saw the fifth episode of The Assassins series Which is shown on the channelDMC In conjunction with its presentation on the WATCH IT platform, a dialogue between Omar Khayyam and his wife in which I mentioned Omar Khayyam’s calendar, so what is it?
Firstly, it must be mentioned that Omar Khayyam Central character in The Assassins series He was famous for his algebra and worked in determining the annual calendar for Sultan Malik Shah, which became the Persian calendar followed to this day..
According to the book “The Science of History: A Study in Methods and Sources” by Dr. Ismail Sami, Khayyam developed what is known as the Jalali calendar, which is a Persian calendar attributed to the Seljuk Sultan Jalal al-Din Shah, Sultan of Khorasan, who ordered him to prepare it in the year 468 AH, 1075 AD, and it is an Islamic solar calendar. He developed it with eight Muslim astronomers, headed by Khayyam, and it was no less accurate than the Gregorian calendar, even though it preceded its appearance by more than 500 years, and it is still in use today in Afghanistan, and it was used in Iran until the year 190, when it was replaced by According to the Hijri calendar, the first sign of Libra determined the beginning of this calendar, and it corresponds to the tropical year in Persia.
The basis for establishing the solar Hijri calendar is the beginning of the first year of the Prophet’s Hijra, and then calculating the years from that time according to the solar calendar, not the lunar calendar. The first day of the solar Hijri calendar is 1 AH (Farvardin) in the year 1 of the solar Hijra, which fell on Friday, Shaban 29, 1 year before the Hijra. March 19 Julian AD (March 22, 622 AD).
The months of the calendar are divided into 12 months, the first six months of which are 31 days and the five months that follow are 30 days. The last month is 29 days in a simple year and 30 days in a leap year.