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Dark Age Obscured (History)
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aurelius



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Under a cloud

Over on the Second Dark Age thread much has been said on the provenance and accuracy of the major British annals in reporting human on human events. In this short topic I shall attempt to relate the annals to the most important event we can detect of a non-military or religious nature which happened during the sixth century. You’d think there’d be more than a passing mention, right?

Unfortunately, a great weakness of the Anglo-Saxon Chronicle is its apparent blindness to one of the greatest physical blows to the equanimity of the troposphere (the lowest level of the atmosphere where all the weather takes place), ever.

We know something untoward occurred because we have contemporaneous accounts of a mysterious dust cloud around 535-536 CE in the conventional chronology. This caused widespread hardship in Europe and beyond for over ten years and was witnessed in the contemporary accounts of Procopius (c.500 – c.554), John the Lydian (b. 490) and others.

As far away as China, the diligent astronomers of the day who had been fastidious in recording celestial events for several hundred years, searched for Canopus, one of the brightest stars in the sky, for astrological divination. Canopus is not visible from British latitudes but would be between 20 and 30 degrees north of the equator - so we are talking Xian (Chang an) rather than Beijing. Their search was in vain.

Records from southern China indicate a drought, famine, yellow dust, and just to add variety, summer frost and snow in 539.
Back in the West, a chronicle attributed to Bishop Zacharias of Mytilene (465 – 536) reported:

“The Sun began to be darkened by day and the Moon by night...the winter in Mesopotamia was a severe one, so much so that from the large and unwonted quantity of snow the birds perished...”
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aurelius



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Blasts from the past

So what caused this crisis in the Northern Hemisphere? The Greenland ice cores register a strong sulphate layer dated to 533/4, + or – two years. Another in the Antarctic archive (though less securely dated), suggests a large eruption. Krakatau may have erupted around this time; others think that the culprit could be Ilopango in El Salvador, whose discharge of ejecta was one of the greatest in history, and is blamed for disrupting Mayan Society. Ilopango blasted out even more than the 1883 Krakatau eruption and may have been on a par with Tambora (1815).

However, there is yet no consensus which volcano was the candidate, or if there was only one; using more ice cores than any previous study, and matching with tree ring data, the Desert Research Institute in the U.S. has published findings which support two consecutive eruptions, one in 535/6 in the northern hemisphere and a second in 539/540 in the tropics, which together kept temperatures cool until 550 CE.
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Mick Harper
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One problem you're going to run into is that 'volcanic winters' have very different effects in different parts of the world -- and therefore cannot necessarily be reflected in either ice-core samples or annals. But do go on.

Krakatoa 1883 produced vivid sunsets. I wonder if that is the sort of thing annalists would notice.
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aurelius



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Mick Harper wrote:
One problem you're going to run into is that 'volcanic winters' have very different effects in different parts of the world -- and therefore cannot necessarily be reflected in either ice-core samples or annals. But do go on.

Krakatoa 1883 produced vivid sunsets. I wonder if that is the sort of thing annalists would notice.


I'm backing that at least one was tropical:

According to the data, nearly all extreme summer cooling events in the northern hemisphere in the past 2,500 years can be traced to volcanoes.

The researchers detected 238 eruptions from the past 2,500 years, they report today in Nature. About half were in the mid- to high-latitudes in the northern hemisphere, while 81 were in the tropics. (Because of the rotation of the Earth, material from tropical volcanoes ends up in both Greenland and Antarctica, while material from northern volcanoes tends to stay in the north.) The exact sources of most of the eruptions are as yet unknown, but the team was able to match their effects on climate to the tree ring records.


I'll look into the sunsets (not directly, of course)...
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aurelius



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Ice in the Sun

We have already seen on the Second Dark Age thread that the closest phenomena we have to a benchmark measure of astronomical observation, Halley’s Comet, with its period of 75 years, promised much in verifying the British annals but, much like the variations in its brilliance, it ultimately fell short. Famously the ASC duly recorded its 1066 appearance, but failed miserably on every other occasion between 374 and 1145.

It’s not as if comets went unrecorded: the ASC thought there was a ‘comet-star’ in 678; again in 729; several comets ("cometa") in 891-2; 905; 975 and 995. On most of these occasions the English ‘sightings’ are replicated by the much more consistent and diligent Chinese records. There is no reason not to believe that these sightings may have been of impressive long-period (such as are not likely to be seen more than once in a lifetime because they have a more elongated orbit) comets which may have outshone Halley’s.

The Annales Cambriae and Annals of Ulster fare little better. Again, there is no obvious corroboration of Halley’s when compared with the Chinese records, with the possible exception of the 912 appearance on which the Annals of Ulster are ambiguous. Even the signature 1066 pass is missed by these sources. And yet – again - it’s not that comets didn’t pique their interest: for example in 917:

“the heavens glowed with comets”,

according to the Annals of Ulster.
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Hatty
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The Annales Cambriae and Annals of Ulster fare little better. Again, there is no obvious corroboration of Halley’s when compared with the Chinese records, with the possible exception of the 912 appearance on which the Annals of Ulster are ambiguous. Even the signature 1066 pass is missed by these sources.

Would this comet appearance be why 1066 was written up as the date of the Norman Conquest? A historic date surely can be made to coincide with a memorable occurrence. Is there independent corroboration not from the British Isles (and not a tapestry)?
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Mick Harper
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According to the data, nearly all extreme summer cooling events in the northern hemisphere in the past 2,500 years can be traced to volcanoes

Notice that phrase "nearly all". In AE we have a principle 'same outcome, same cause'. I would dearly like to know if this is being used in the sense "except for those caused by x, y and z" or in the sense "some haven't been dealt with yet" or (the most likely) "let's not be too dogmatic, let's not be seen to be too dogmatic, because frankly this is not an area in which any of us can be sure and it could be embarrassingly overturned at any time."

The researchers detected 238 eruptions from the past 2,500 years,

Alarm bells should be ringing.yet nobody seems to be hearing them. There are probably 238 eruptions every year so selectivity is being applied on the grandest of scales.

About half were in the mid- to high-latitudes in the northern hemisphere, while 81 were in the tropics. (Because of the rotation of the Earth, material from tropical volcanoes ends up in both Greenland and Antarctica, while material from northern volcanoes tends to stay in the north.)


A distinction should be drawn between 'material' and 'material effect' It may be that particles in the atmosphere can end up in ice deposits without affecting the weather.

The exact sources of most of the eruptions are as yet unknown,


This is weird. If they do not know how can they tell where north and south hemisphere volcano debris ends up?. We have just been told that about half, say 120, were mid/high northern latitudes, 81 in the tropics, leaving 37 in the south (all latitudes). If they don't know 'the exact source' then they must be going by the indirect evidence ie the ice samples. So now this is a complete circularity.

but the team was able to match their effects on climate to the tree ring records.

If the source is unknown (ie in the absence of historical or local evidence) volcanic eruptions can only be inferred from ice core data or tree ring data. So another enormous circularity.
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aurelius



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Hatty wrote:

Would this comet appearance be why 1066 was written up as the date of the Norman Conquest? A historic date surely can be made to coincide with a memorable occurrence.


You're stealing my thunder Hatty! I was coming to that...
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aurelius



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Hard Rain

Comet impacts cannot be ruled out as a cause of the cloud of murk. In 2013, the website Livescience.com reported, ‘Halley’s Comet may be linked to a famine 1,500 years ago’. A new study of ‘extra-terrestrial stuff’ found in a Greenland ice core by Columbia University’s Lamont-Doherty Earth Observatory found high levels of tin among the dust, which they say is more consistent with cometary matter than a volcanic eruption. Significantly this was deposited during the northern hemisphere spring, coincidentally when the Earth encounters the Eta Aquarid meteor shower as it crosses through debris left in the orbital path of Halley’s Comet.

According to Columbia’s Dallas Abbot, the 530 AD pass of Halley’s, which as I have found was apparently unnoticed by British chroniclers, was one of the brightest, typical of a comet that was shedding some of its mass.

Should a large chunk of that debris several hundred metres wide eventually crash into our atmosphere and explode, enveloping the Earth in a cloud of dust, that could possibly explain a global cooling of several degrees as the Sun was filtered out. But it would have to be bigger than the Tunguska event, which as far as I am aware did not have a hemispheric-scale effect.

All the more extraordinary then, that the best the ASC can offer is an eclipse of the Sun in 538 for a few hours (which orthodoxy says was actually in 536 -analysts are ‘at a loss’ to find a calculated eclipse for that date). Around 535-6, our chronicler was more concerned with the assumed control of the Isle of Wight by Stuff and Wihtgar.

There’s nothing in the AC or A of U for 530 – 540 on heavenly events at all. Reminds me of a cartoon where an alien landing goes unnoticed because everyone is fiddling with their mobile phones.
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Mick Harper
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best the ASC can offer is an eclipse of the Sun in 538 for a few hours

Those of us who witnessed a full eclipse -- after all the best you can get -- will be puzzled by 'a few hours'. It was full for a few minutes, partial for (what?) twenty minutes tops. And of course, apart from the birds not twittering, had nil effect on man or beast. Which is not to say that it might not be mentioned in passing as an interesting event though since an annal might only have twenty words for all the events of a given year, even that seems to be pushing it. Lunar eclipses are so common (and partial solar eclipses not exactly rare) that the phenomenon shouldn't overly-excite educated Anglo-Saxons.

PS Forgers trying for a bit of faux detailing is another matter.
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aurelius



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Mick Harper said:

Krakatoa 1883 produced vivid sunsets. I wonder if that is the sort of thing annalists would notice.


This lot didn't. Which is all grist to my particular mill. They do remark "the Moon was covered with blood" which I take to be a description of an eclipse, but that is all.

Given that eclipses are a relatively common sight compared to comets they are vastly under-reported by the British annals, even allowing for poor weather. I wasn't going to post up anything about them but now I'm having second thoughts.
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Boreades


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Any mention of Arthurian Wastelands? As in, fabled disaster zones as folk memory of volcanic/meteorite activity that had extreme effects in Britain. Somewhere around the Britons being forced to move to Brittany, and arriving Saxons finding a deserted countryside.
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aurelius



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Boreades wrote:
Any mention of Arthurian Wastelands? As in, fabled disaster zones as folk memory of volcanic/meteorite activity that had extreme effects in Britain. Somewhere around the Britons being forced to move to Brittany, and arriving Saxons finding a deserted countryside.


There is no mention of Arthur in the ASC unless it is under a variant spelling which I have not anticipated. He gets one mention in the Annals of Ulster (only in so far as he succeeds Uter Pendragon in 467 CE) and two in Annales Cambriae, 516 (Battle of Badon) and 537 (Battle of Camlann, death).

There is no mention of Brittany as such in AC or AU or in ASC prior to 748 CE. After that I haven't checked.
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Mick Harper
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Let's not forget that the Arthurian industry was launched in the twelfth century!
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Boreades


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I'm quite willing to believe Arthur is too myth to even get a mention in the ASC. But it's the wastelands I'm interested in. They seemed to me to have struck a discordant note in the narrative. Perhaps it was a different narrative patched in from a different source?
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