Mathematics and the Battle of Clontarf

"The Brian Battle," as it was also called, was a turning point in Irish history. However, historians have long debated the exact nature of that turning point. Those with a patriotic Irish heart liked to portray it as a cleansing of Ireland by a native Irish hero, Brian Boru, who led his Irish armies to defeat the invading Vikings. That romantic reading fed the hearts of those who, likewise, wanted to cleanse Ireland of another bunch of invading Germanics.

More sober historians pointed to a lot of factionalism within the Ireland of the day, and suggested that it was probably more of a civil war in which the Vikings backed the losing side.

Now, a mathematical model suggests that the romantics were right, or at least more right than not.
To perform the study, the academics examined Cogadh Gaedhel re Gallaibh (“The War of the Irish with the Foreigners”), a chronicle from the early twelfth-century that reported on events in Ireland between 967 and 1014. They wanted to know how all the Irish and Viking characters in the text fit together in a network, monitoring whether the interactions between them were benign or hostile. They developed a mathematical measure to quantify whether hostility in the network mainly connected Irish to Irish or Irish to Vikings.

They then calculated the difference between the measure of hostilities between each type of character (Irish and Viking) and what would have been hostile interactions in the network, indiscriminate of whether characters were Irish or Viking.

A positive value of the resulting measure would signal Irish civil war and a negative number would reflect an Irish versus Viking conflict. The results gave an overall negative value suggesting that the text mainly describes an Irish against Viking conflict.

However, because the negative value was moderate (-0.32 on a scale from -088 to 1) they suggest the text does not describe a fully “clear-cut” Irish versus Viking conflict. Instead, the network portrays a complex picture of relationships and social networks of the time.
We tend to be inclined to doubt romantic opinions, but sometimes romance wins one.

6 comments:

  1. Maybe one of the factions backed the losing vikings.

    Maybe the vikings incited a civil war to facilitate invasion and were defeated anyway.

    Eric Hines

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  2. Well, they'd been there for a while. One reason to take the 'civil war' narrative seriously is that they had been around long enough to make friends and intermarry.

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  3. For example, Gormlaith -- at one time Brian Boru's wife -- also married Olaf Cuaran and gave birth to Sigtrygg Silkbeard. She's mentioned in the Icelandic sagas as well as the Gaelic accounts.

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  4. E Hines idea occurred to me as well, though it doesn't eliminate the narrative of expelling Vikings. If there was general antipathy to Vikings, that would include antipathy toward those tribes which were perceived as too close to them, and not loyally Irish as they should be. With dense relationships, there would always be some angling for advantage, some protection, some favoritism. Yet a core of nationalists whose overriding concern was "Vikings Out" would have complicated relationships with those who were mostly allies but cheated on the side to better position their tribe or family for after the war.

    My own prejudice is that tribe wins out in people's affections, but they try to grab and extra few bucks on the side on the way out.

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  5. Interesting method.

    If you like Irish whisky, Clontarf 1014 is quite good. From their site:

    "Our whiskey celebrates that courage to take a stand and make a sacrifice to bring about what you believe in."

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  6. "We tend to be inclined to doubt romantic opinions, but sometimes romance wins one. "

    I remember when I first came to see what was going on at the Hall, thinking that it was interesting, but that Grim was too much a romantic for me to take entirely seriously across the board.

    After a while, I learned to take romantic notions much more seriously, and I'm better for it.

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