When evaluating chronicles such as Chapter 18 of the Great Treasure, nothing could provide better corroboration than an eclipse. We are thus fortunate that our text mentions just such an event:
ubiahria šabaṭ daula ḏ-mišanuiia barba habšaba zipa lšamiš nigaidẖ mhauai elẖ ḏ-malka ḏ-babil lbabil nitia uqiniana ḏ-babil lbabil nitia ubṭur anašia lagaiia lpadakšar nimṭun
And in the month of Shabāṭ (Aquarius), [Qam] Dawla [according to the style] of the Meseneans, on Wednesday, the overtakes the Sun. It is indicated that the King of Babylon comes to Babylon, and the possessions of Babylon come to Babylon, and the lagaiia overcome the Padishah (Phl. Padixšā) in the “Mountain of the People” (Phl. Turānšahr).
Here it is worth mentioning a few words about the Mandaean calendar. This entry comes immediately after the entry for Year 795 of Pisces, which is equivalent to 474 in the Gregorian calendar. According to Drower, the month of Shabāṭ is also known as Qam Dawla (hence the expression daula ḏ-mišanuiia), and colloquially known as Awwal Shetwa. It is the first month of the year, corresponding to the Pahlavi Frawardīn, so we have already moved into 796/475. Arba Habšaba simply means Wednesday. On this day, the Lie reaches the Sun, according to our text.
In his 1938 article on “An Ancient Persian Practice Preserved by a Non-Iranian People,” S.H. Taqizadeh (615) identifies this event as an eclipse, and notes that there was an eclipse on Wednesday, July 14, 622 (the 26th of Frawardīn). This is true, but it was only visible from Antarctica. Two years later, another eclipse occurred on a Thursday, June 21, 624 (the 4th of Frawardīn), but it was visible in southern Iraq only as a partial eclipse, starting just 23 minutes before sunset, and did not reach maximum eclipse until half an hour after sunset AST. Clearly neither of these are appropriate candidates to reflect the world’s falsehood overtaking the Sun.
On the other hand, if we look for an eclipse that took place on a Wednesday in the month of Frawardīn in 475, we conveniently find an annular eclipse on Wednesday, June 19, 475, which would have been visible throughout Iraq, dramatically reaching maximum eclipse at 12:12pm AST. Even more amazingly, if my calculations are correct, this would have occurred on or around the 1st of Qam Dawla/Frawardīn, which is Dehwa Rabba, the Mandaean New Year. An eclipse at noon on New Year’s Day! Clearly, this is the best candidate for the phenomenon described in the text.
What else happens in this year? There is a reference to ṭur anašia, literally “the Mountain of the People,” which I take to be an folk etymology of the Pahlavi Turānšahr, “empire of Turan.” A group of people described as the lagaiia overtake padakšar, which Lidzbarski derives from padixšāh “Padishah.” Instead of reading this passage literally, however, he translates Padishah metaphorically as Herrschaft “lordship,” and interprets it to mean that the lagaiia came into power, a concept that is elsewhere regularly rendered with the phrase qam bmalkuta.
Who are the lagaiia? Nöldeke (1875, 141, n.5) derives this hapax from a verbal root l-g-y, an otherwise unattested variant of l-g-l-g, “to stammer,” making lagaiia the “stammerers” or speakers of an unintelligible language. Lidzbarski and all who follow him gloss this term as barbarians. In my opinion, these are none other than the Hephthalites or White Huns, who reappear in the account for 800/479, and who would eventually kill the Sasanid king Peroz I in 484 (AP 805). It was sometime around this very time (the mid-470s) that he led another campaign against them and was ignominiously captured by them, or quite literally “they overtook/attacked the Padixšāh in Turān.” Consequently, the Sasanids were forced to ransom the future Kavadh I, who was born in 794/473, giving us a terminus post quem for this incident. 475, the year of the eclipse, fits perfectly with this narrative.