The wind in the English Channel backed suddenly to the south on this day 934 years ago. William Duke of Normandy was pleased. For nearly a month at St Valery-en-Somme he had . . . watched the weathercock upon the Minster's tower;
First Boreas, blowing from the north, diverted Auster
From the shore, and there were tears of sorrow;
But Auster from the south returned, and he rejoiced.
The change in wind direction allowed William to begin his great adventure: to take by force what he believed belonged to him, the crown of England.
The Duke's claim to the English throne was supported by Pope Alexander II, and recruits flocked to his banner from all over Europe. His fleet had assembled in early August 1066 at the mouth of the Dive river on the northern coast of France.
But the wind, as we have seen, was from the north, and Norman vessels, having only one rectangular sail, needed an almost following wind for headway, so William had to wait. At the beginning of September the wind backed west for a time, and he was able to move his ships somewhat closer to his ultimate objective, to St Valery; but then the northerlies resumed, and there he had to settle down again, and wait.
This hoped-for change finally occurred on September 27th. William grasped his opportunity and set sail immediately, landing at Pevensey in Sussex on September 28th, 1066. Two weeks later he gained his title "the Conqueror" by defeating the forces of King Harold near the town of Hastings.
It is arguable that if the northerly wind had lasted just another week, the course of history might have been entirely different. While William was landing at Pevensey, Harold was busy in the north repulsing an attack by Hardrada, King of Norway.
This he did successfully at the battle of Stamford Bridge. But if William's departure had been further delayed to allow Harold time to reach the south of England, he might well have deprived the Normans of their easy landing.
In the event, William defeated Harold on October 14th, and the subsequent conquest of England was, as we know, systematic, ruthless and complete.
It may be that the English should not have been entirely surprised by their defeat, or at least not surprised that something catastrophic should befall them. The night skies during the summer of 1066 featured one of the regular appearances of Halley's Comet, and its presence over the battle-field is prominently commemorated in the Bayeux Tapestry. Such apparitions were well known at the time as harbingers of doom - and this one had obviously aligned itself on William's side.