Science and the Anglo-Saxon Chronicle

A few weeks ago, Japanese researchers published their discovery that radiocarbon dates coming from the growth rings of cedar trees corresponding to the year 774 CE were way out of whack, suggesting that there had been some celestial event causing a burst of high-energy radiation that year. But they could find no record of a supernova or similar event in that year. Enter Jonathon Allen, an undergraduate biochemistry major at the University of California Santa Cruz. By searching the internet, he found that some texts of the Anglo-Saxon Chronicle include this entry:

A.D. 774. This year the Northumbrians banished their king, Alred, from York at Easter-tide; and chose Ethelred, the son of Mull, for their lord, who reigned four winters. This year also appeared in the heavens a red crucifix, after sunset; the Mercians and the men of Kent fought at Otford; and wonderful serpents were seen in the land of the South-Saxons.

Was the red crucifix the missing supernova? Maybe so. And maybe it was behind the sun -- it was seen just after sunset -- which is why more people didn't notice it and write about it.