An example of the « Persian Royal Calendar »
Some chronological data in Aphrahat’s Demonstrations
Aphrahat (Pers. Frahād), a Jew before his conversion to Christianity, who lived within the Persian kingdom (Ērānšahr) in the fourth century, who expected (and possibly collaborated with) Constantine to be successful in his preparation to invade Persia, who is ironically known to us as the “Persian Sage”, has given, in his Demonstrations, these chronological data.
The Wèi-shū and the Persian calendar
The Wèi-shū, or the Annals of the Wèi (dynasty), was written by Wèi shōu (506-572 A.D.), a high-ranking civil servant of the dynasty of the northern Qi (北齊). The account of Persia in the sixth century is found in chapter 102 of this book. It is almost identical with another Chinese account, the Běi shǐ (北史), or the book of the History of the dynasties of the North, completed by Lǐ yánshòu (李延寿) in 659 A.D., chapter 97.
Wèi shōu gives a few Persian dates, not according to the Persian “royal” calendar, but according to the Chinese lunar calendar. If we try to use his information by searching in the possible range of years to find one in which the 1st day of the 12th Chinese month was the 16th day of the Persian month Mihr (i.e., the feast day of Mihragān), and the 20th day of the 1st lunar month was one of the five additional days of the Persian year, we notice that these two dates correspond best to the fifteenth year of the reign of Xusrō Anōšervān (≈ 545-546 A.D.) –note that Wèi shōu completed his annals in 554 A.D.
اين نامة دين کامه اج بهر ِ پاسخ ِ نامه ای که دستور و دستورزاده موبد کاوس و دستور داراب ولد ِ موبد سهراب که سال هزاروسدونه يزدجردی از کشور ِ هندوستان از بندر ِ مبارک سورت رقم نموده به جهت دستوران ِ ايران زمين ساکن ِ يزد و کرمان ارسال داشته اند
 . 1740 A.D.
An extract from a letter from Kirmān addressed to Manekjī Navarōzjī
From Mullā Fērōz
Some comments on Dastur Aspandiārjī Kāmdīn’s work on “the kabīsa”
In 1195 A.Y./ 1826 A.D. the Pārsī Dastōr Aspandiārjī Kāmdīn of Broach published a book, in Surat, to offer a historical account of the ancient leap-year of the Pārsīs, that is, the truth of the kabīsa (“intercalation”) in the ancient Zoroastrian calendar. Mullā Fērōz began writing a series of letters in the Pārsī newspaper, the Bombay Samācār (સમાચાર), to refute his thesis. Dastōr Aspandiārjī had used for the support of his view a Persian book called the Zīj i Jalālī. Mullā Fērōz suspected that the above book was composed sixty or seventy years ago by a Pārsī Dastōr (Aspandiār’s father?) to confuse the common Pārsīs. Indeed the Zīj i Jalālī (or, Malikšāhī) had been written by Xayyām in the 11th century; but the absence hitherto of any manuscript of that zīj enhances the doubt of Mullā Fērōz. Notice that, during the same period of the kabīsa controversy, another Pārsī Dastōr, Edaljī Navrōjī, used the treatise attributed to Cāndā (16th century) to prove the practice of intercalation in the ancient Pārsī ritual calendar. In the thick of the calendar controversy, and some months after the printing of his book, Dastōr Aspandiārjī passed away. Mullā Fērōz’ request as regards the text of the above zīj met no response.