  Recently, a significant carbon-14 enhancement in the year 994 in tree rings
has been found, suggesting an extremely large cosmic ray flux event during a
short period. The origin of this particular cosmic ray event has not been
confirmed, but one possibility is that it is of solar origin. Contemporary
historical records of low latitude auroras can be used as supporting evidence
for intense solar activity around that time. We investigated the previously
reported as well as the new records found in contemporary observations from the
990s to determine potential auroras. Records of potential red auroras in the
late 992 and early 993 were found around the world, i.e. in the Korean
Peninsula, Germany, and the Island of Ireland, suggesting the occurrence of an
intense geomagnetic storm driven by solar activity.
