24 April 1066 A hairy star, strange, enormous, was seen in the air on Tuesday after Little Easter, at the eight of the kalends of May [24 Apr] with the twenty sixth of the moon thereon. Such was its size and brightness that men said it was a moon, and to the end of four days it remained thus - The Irish Annals

What was this strange and apparently supernatural object that flew across the sky over Ireland in April 1066 AD? To people at that time such apparitions in the Heavens struck doubt and fear into their hearts and they were seen as a portent of evil doings to come. The Irish Monks duly noted its passing and no doubt prayed that whatever it portended it would pass over this Country without harm.

In fact what they witnessed was a comet - Halley's Comet in fact. It is the best-known of the short-period comets, and is visible from Earth every 75 to 76 years. Halley is the only short-period comet that is clearly visible to the naked eye from Earth, and thus the only naked-eye comet that might appear twice in a human lifetime. Other naked-eye comets may be brighter and more spectacular, but will appear only once in thousands of years.

This celestial phenomena did indeed harbour a portent of doom, but it was not in Ireland that its misfortune struck but in England. For it was in 1066 that the King Harold of the Saxons was overthrown and killed at the Battle of Hastings during the invasion of England by William the Conquerer of Normandy - who then took the Kingdom of England for himself.

The Comet was last seen over Ireland in 1986 - but don't worry its not due to return until 2061 AD!!!