Plague among the nuts

David Woods was looking at the early Irish chronicles and he noticed something very odd. There are clusters of entries recording large mast crops. Mast? In Ireland, that would be mostly acorns..  In these sparse annals that normally only record battles, deaths,  and other major events, why record large acorn falls? The only typical use for mast / acorns is to feed pigs. But the chronicles ignore pigs. To make it even odder, there are no other entries in the Irish chronicles for any other specific crop. There are only a couple references to bread failure, but as Woods notes, this is still not a reference to a specific crop.  Further, there is no antique precedent for recording mast crops. Woods notes that none of the antique chroniclers, most of whom did record natural disasters and bad omens (like a red moon or comet) recorded mast crops. So what is going on here?

Knowing that chroniclers decided what type of thing to record in the chronicles by reading earlier entries, Woods focused in on the earliest entries of large mast falls. The earliest entry in the Annals of Ulster comes in 576: “Scintilla lepre 7 habundantia nucum inaudita” (“a spark of leprosy and an unheard of abundance of nuts”). The conjunction of some type of skin illness with the large nut fall suggests that the chronicler may have misunderstood his source. It is likely that this early section of the Annals of Ulster was constructed retrospectively from older records. Woods (p. 498) suggests that “this entry had originally described an occurrence of a magna pestis glandularia in addition to a scintilla lepre, but the editor or copyist misunderstood the term glandularia.”

The Latin term glandularius is the root of our word for gland; etymologically, glandula means ‘little nuts’ because this is what they felt like when palpated. There is at least one other example of a plague record using glandulara as a descriptor. In c. 660 the Burgundian ‘Chronicle of Fredegar’ describes the 599 plague of Marseilles as a cladis glanduaria.

For Woods hypothesis to work, the copyist/chronicler must have mistaken pestis to mean a general calamity rather than a specific disease (or any disease for that matter). Later longer entries in the annals suggest that large mast crops could indeed be problematic by blocking streams and presumably causing flooding. The record of an “abundance of mast” in 672 fits with Woods theory that this “mistaken paraphrase” occurred when the ‘Iona Chronicle’, the parent of the Annals of Ulster, was compiled from older records in the 670s. A recent large mast crop could have prompted the chronicler’s paraphrase mistaking glandular plague with a glut of acorns.

When the plague first swept across Europe it took four years to arrive in Ireland. Plague was first reported at Pelusium in 541, Constantinople in 542 and reached Ireland in 545 (according to the Annals of Ulster). If we have a probable plague entry in Ireland we should find other plague records in Europe or the Mediterranean, and so we do. Bishop Maurius of Avenches dates an outbreak of “glandular” plague to 571. An outbreak was also recorded in Constantinople by Spanish visitor John of Biclaro in 573. The Irish record in 576 fits in. Given how sparse sixth century records are, this is about all we should expect for a wave of plague moving across Europe in the 570s.


David Woods (2003). Acorns, the Plague, and the ‘Iona Chronicle’ Peritia (17-18), 495-502.

12 thoughts on “Plague among the nuts

  1. mast blooms go in cycles. in years with large acorn production, there will be a lot of very well fed squirrels, mice and other vermin. the following year there will typically be high births among these species. some of them are vectors for human diseases. there can also be subsequent bursts in the populations of the animals which prey on them.

    a productive masting season may therefore be the harbinger of disease, harvests attacked by unusually large numbers of vermin, and other ecological phenomena important to human well being.


  2. In 2008 we had NO acorns at all in Virginia. I believe it was the same in a large part of the east coast USA.


      1. There was a lot of “up and down the east coast” talk about the vanishing acorns that year. This CNN article mentions “pockets” of disapperances but also leans toward “everywhere”:

        Slashdot claimed “across the country”

        Were the vanished acorns the exception or the rule? I was in VA/DC/MD and we were seeing the shortage everywhere.


  3. Last year in my area we had a large acorn crop. We’ve been fighting mice ever since. In an ordinary year we’ll catch 5-6 mice all winter, last winter it was at least 30. Luckily they haven’t gotten past the basement so no plague yet.

    I have heard of a correlation between hanta virus and large pinon nut crops in New Mexico. I don’t know if it’s been proved or if it’s just tabloid journalism.


  4. Acorns feed more than pigs! They are a major source of fat for deer and bear just before winter, when it’s needed most. And they were a major food source for Amerindians (and in some cases still are). I wouldn’t be surprised if acorns served as a famine food in Europe and elsewhere. I think the tie with plague is coincidence. Bad weather=poor harvest, followed by crowded winter living conditions. Here in SW Oregon most summers are dry. Result: acorn crops are unpredictable. Every few years there is a bumper crop. We had one last summer.


    1. This post was about a poor translation of a plague record being mistaken for a record of a large mast fall. Later records of large mast falls, often in famine years, are probably indeed records of mast falls. I had wondered about people eating acorn flour but I don’t know of any evidence of that in Europe.


    1. Not really. From what I have read there isn’t a direct relationship between any one factor and acorn crops. It may be a multi-year effect related to amount of water, temperature in winter and summer, etc. Trees may reproduce on a more long term cycle than a single season.


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