The visit of future King of England.
Sweyn Forkbeard came to Sarum in 1003. His intentions were not peaceful and he was not welcome.
Sweyn Forkbeard and his father Harald Bluetooth didn’t get on. Sweyn became a Christian around the time Harald recanted the faith. Sweyn was King of Denmark for nearly thirty years but of England for only five weeks 1013-14. He dethroned his father in Denmark and Æthelred the Unready in England. King Canute was his son. In the Bayeaux tapestry Edward the Confessor is shown sporting a divided beard. Sweyn before him obviously had the same facial hair fashion.
There was a massacre of Danes including Sweyn’s sister and brother in law in Oxford in 1002. He came to invade England for a second time in 1003 looking for revenge. He sacked Exeter, then moved on (by sea) to cross Hampshire to sack Wilton and according to the Anglo Saxon Chronicle “Then went he to Sarum; and thence back to the sea”. This source does not say he attacked Sarum, it implies he thought better of it and marched south back to his ships. Perhaps Sarum was too well defended. This predated the Norman defences and motte and bailey but there may have been defensive earthworks on the Wilton side of Sarum to deter him that do not exist today. Deep ditches have been found across the fields between Old Sarum and Stratford. The Saxons (including Alfred) had upgraded an iron age hillfort to a fortified burgh. He did not lack the courage to attack but protracted sieges were not a Viking way of fighting, perhaps he felt it would just take too long. As this also predated the Norman Royal Palace and Cathedral, he may have felt there wouldn’t be enough plunder to be worth the effort, he wanted to get the Wilton booty back to his fleet. It is unlikely he attacked and was repelled as history is the record of the victors and there is no record of this. The last possibility is that he did sack and burn Sarum as he did Wilton and Exeter, this was the outcome recorded about a century later and preferred by some historians. No layer of burning has been found beneath the Norman works though. There is no record of a settlement called Stratford at the foot of Sarum from this period, nor was there eighty years later when the Domesday book was compiled. This could be because these events predate settlement here alongside the Avon but if a settlement had existed and Sweyn had marched through on his way from Wilton via Sarum to the South Coast he probably wouldn't have left much behind.