At the time of writing this book, we found that dates in Persian and English sources were in the Islamic Lunar calendar or Hejri. Since many native English speakers do not grasp the concept of the Hejri calendar, we converted the dates based on the Georgian calendar. We tried to be as accurate as possible, but the sources that had converted the dates and various websites that convert dates had many discrepancies. One reason being that in 10 AH (631/632 CE), intercalation of extra months in the Arabian calendar was abandoned according to Islam as referred to in the Holy Quran in chapter 9, verses 36-37. Before this year, an intercalary month was added to the year every two or three years to keep the lunar calendar aligned with the seasons. So,