837 – Halley’s Comet races past earth at the closest range ever
It is not recorded in The Anglo-Saxon Chronicle. The Chinese astronomers record this year’s occurrence “branched into two tails”. Apparently, this is one of the closest
fly-bys paths the comet has ever taken past earth (see W.S. Tsu in Popular Astronomy, pp. 196-197 and Ian Ridpath’s blog).
In the life about Louis the Pious, the anonymous scribe called the ‘Astronomer’ describes how Louis conducts himself when the comet appears. The king devotes himself to prayers, alms and a little hunting (see Thomas Noble, Charlemagne and Louis the Pious, pp. 292). There is an alternative view, though, that Louis the Pious and the Astronomer observed something other than Halley’s comet (see Scott Ashley in Early Medieval Europe, Vol. 21.1 (2013), pp. 27-49).