The 18th chapter of the right-hand volume of the Great Treasure (ginza rba) represents a dramatic break from the rest of the text, no more so than in its genre. It’s a chronicle! Various scholars, including Lidzbarski, read references to Islam into its final pages:
This tractate is the only one whose date of completion can be narrowly isolated. On page 414, the duration of Arab rule is assumed to be 71 years, which cannot be said after the first years of the 8th century. The assumption of so brief a duration of the Arabian empire, for which the number 71, in addition to numbers 70 and 72, is adopted, is however more probable for the first years of Islam, so that the tractate ought to have been redacted around the middle of the seventh century.
At first glance, Lidzbarski’s argument seems logical enough, but it requires us to make the following assumptions:
- In order to satisfy the expectations of their new Muslim rulers, Mandaeans redacted their texts into a new holy book (as reflected in JB 22: “Who is your prophet? Tell us whom your prophet is, tell us what your scripture is, tell us whom you worship”);
- In this book (redacted explicitly to impress their new rulers), they insert a prophecy about the impending demise of said rulers;
- This prophecy unfolds over a surprisingly short and specific time frame—possibly even within the lifetime of some of the redactors. Once this time frame concludes, they opt not to re-redact the prophecy from their text, but rather preserve it for all posterity.
On this same page (407), he presents (but seemingly discards) another possibility:
The “kings of the Arabs” are set before the fall of Sasanid rule. They are probably the Arab kings of al-Hira, on whose territory a portion of the Mandaeans dwelt.
Let us then assume that these “kings of the Arabs,” who reign for 71 years, are the Lakhmids of al-Hira and not Muhammad and his successors (who do not otherwise appear elsewhere in this chapter). Nu’man III, the last ruler, was executed by Khusraw II Parviz in 602, whereupon the Lakhmid state was absorbed by the Sasanids. That brings us back to 531. What was happening in al-Hira at that time?
The Sasanian ruler Kavadh I passed away in 531, and with the ascension of a new ruler, Khosrow I Anushirwan, the Lakhmid ruler Al-Mundhir III ibn al-Nu’man was restored in al-Hira. Al-Mundhir had been briefly dislodged by al-Harith al-Kindi, likely at the behest of Kavadh, who was likely a devotee of Mazdak. His successor Khosrow, on the other hand, had Mazdak excecuted, and likely permitted al-Mundhir to reclaim al-Hira. Therefore, 71 years corresponds exactly to the rule of al-Mundhir and his Lakhmid successors over al-Hira.
The text shares with us some of the other events that were happening in the world at that time:
When the world is in Year 850 of the Fish, a great plague will occur. Then, after the Persian kings, there will be Arab kings. They will rule 71 years. In the years of those Arab kings, the world will be false.
To my mind, this immediately recalls the Plague of Justinian, which originated in China, and traveled thence to the Eastern Roman Empire, where it was first attested in 541 (specifically in Egypt). Could this be the earliest attested reference to the great plague, as it wended its way across Asia and arrived within the borders of the Sasanid empire? The source for its emergence in the West, Procopius, notes that it was preceded by strange weather, a year without proper sunlight:
And it came about during this year  that a most dread portent took place. For the sun gave forth its light without brightness, like the moon, during this whole year, and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear nor such as it is accustomed to shed. And from the time when this thing happened men were free neither from war nor pestilence nor any other thing leading to death.
In the entry for Year 803 of the Fish (presumably 484, if 531 is Year 850 of the Fish), two natural disasters are mentioned, book-ended by half a century. The first (803/484) is the flooding of the land of Babylon and the meeting of the Tigris and the Euphrates, which happened sometime in the second half of the 5th century (resulting in Ctesiphon becoming divided by the Tigris, and precipitating its decline). The second (853/534) is a famine in the land of Gaukai:
Concerning it [in Year 803 of the Fish], it is said that when Saturn is in Scorpio, and it emerges from Scorpio and enters Leo, the great Euphrates will overflow as far as the Tigris and in the land of Babylon, fifty years before the land of Gaukai goes to ruin. Were you to request a kapīč (1/10th of a peck, or about 873 grams) of grain in the land of Gaukai for five staters (roughly 43 grams of pure gold, worth about 1,775 USD today), we would look but it would not be found.
Citing al-Mas’udi, Michael Morony (2005, 137–38) notes, “This [Gaukai] had been one of the most fertile provinces of the Sawad before the lower Tigris began to shift away from its southeastern part in the mid-fifth century,” thus providing us with a terminus post quem for the situation described in the Great Treasure. The date of the famine fifty years later corresponds rather nicely to the year without sunlight recounted by Procopius and other authorities. These two dates also bookend the rise of a false messiah:
It is revealed concerning it that a false messiah will come, and he will become master of the whole world, sit on a great throne, and upon it deliver a judgment to cast out the judges. From the east to the west, he will come in one day, until the bricks of the walls bear witness to him.
Most who read this passage conclude with Lidzbarski that it refers to Muhammad (“This fits the simultaneous appearance of a false messiah, that is, of the prophet Muhammad”). It is all the more strange, then, that the author does not mention Muhammad by name, as he does elsewhere in reference to the prophet of Islam.The imagery used is quite clearly Christian, as would befit the Lakhmids. They were adherents of the Church of the East, and would naturally describe an anti-Christ by drawing directly upon accounts of Christ-like miracles, such as Matthew 24:27 (“For as the lightning comes from the east and flashes as far as the west, so will be the coming of the Son of Man”) and Luke 19:40 (“I tell you, if these were silent, the stones would shout out”). For the Lakhmids, the anti-Christ was, of course, Mazdak, whose rise to prominence began with the ascension of Kavadh I in 488, and ended with his execution in 529—a period that fits directly between the two historical events described in Chapter 18.
Lidzbarski himself notes the difficulty inherent in reconciling these events with the events of the first Islamic century (414, fn. 3). Once we remove Islam from the picture, the dates and the events that they describe correspond to those known from Western sources with a surprising precision.