Life did not go smoothly for William, Duke of Normandy after his success at the Battle of Hastings and his seizure of the crown of England in the year 1066. His grip on power was not absolute and not everyone in England was happy with the new regime. Sporadic resistance continued for a number of years after the conquest (see English Resistance to the Normans) and in particular in 1075 he faced a threat from within the ranks of his own Norman supporters in an event known as the Revolt of the Earls.
The key figure in the revolt was Roger of Breteuil, the son of William Fitz Osbern, the Earl of Hereford 1 who therefore inherited that title on his father's death in the February of 1071. Roger had developed a close friendship with one Ralph Guader, the Earl of Norfolk and agreed to allow Ralph to marry his sister Emma.
The king William I however, disapproved of such a close alliance between two powerful magnates and forbade the marriage. Roger of Breteuil however, simply took no notice, and according to Simeon of Durham "contrary to the command of king William, gave his sister in marriage to earl Ralph". So the marriage went ahead anyway in 1075 with the wedding celebrations providing the opportunity for the two earls to hatch a plot to "to put the king out of the kingship of England" according to the Anglo-Saxon Chronicle.
It was Earl Roger and Earl Ralph who were the foremost in the foolish plan; and who enticed the Bretons to them, and sent east to Denmark for a raiding ship-army to support them.
the Anglo-Saxon Chronicle
Even for two men as influential as Roger of Breteuil and Ralph Guader the task seeking to unseat the king of England was a fair challenge and they needed allies. So they entered into correspondance with the Danes in order to enlist their support, and the two Norman earls also drew Waltheof 2 the earl of Northumberland into their conspiracy, but this latter decision was a mistake as the earl Waltheof was an unwilling conspirator and promptly spilled the beans to Lanfranc, the Archbishop of Canterbury. On Lanfranc's advice Waltheof sailed for Normandy and admitted all to William and threw himself on the king's mercy.
Thus forewarned, William was able to send word back to England and organise his defences. Wulfstan, the bishop of Worcester, together with Angelwin, the abbot of Evesham raised an army that successfully blockaded the Severn valley and prevented Roger of Breteuil from joining up with the forces of the earl Ralph. Meanwhile Odo of Bayeux and Geoffrey de Montbray moved with another army against Ralph Guader who was camped near Cambridge. Ralph seeing that he was outnumbered, fled to Norwich and back to his native Britanny leaving his English lands in the hands of his wife Emma. Emma seems to have been made of sterner stuff and withstood siege for three months in Norwich before agreeing to surrender the town in return for safe passage to Britanny for herelf and her people.
The Danish assistance now arrived in the form of two hundred ships off the north-east coast under the command of two captains, Cnute Swainson and earl Hacco, but with Ralph Guader fled and Roger of Breteuil bottled up in Herefordshire the revolt was effectively over before it had even started. So the Danes contented themselves with raiding York and looting St Peter's Minster.
On his return from Normandy king William imprisoned both Roger of Breteuil and Waltheof. As to the other supporters of the rebellion, a few Norman knights were banished but the lesser lights of the revolt were punished either by the putting out their eyes, or the cutting off of their hands, according to Simeon of Durham. Roger of Breteuil seems to have spent the remainder of his life in prison but Waltheof, despite his pivotal role in revealing the details of the plot, was subsequently beheaded at Winchester on the 31st May 1076. 3
William I pursued Ralph Guadar to Britanny and laid siege to his stronghold at Dol in October of 1076 but was prevented from completing the job by Philip, king of France who intervened on Ralph's side and drove William away with heavy losses.
In the end the whole revolt was something of a damp squib, but had William not been possessed of prior knowledge of the revolt it might well have proved a more serious threat, although quite what Roger of Breteuil and the other parties to the conspiracy had in mind in terms of the government of England after they'd driven out William is not clear.
The revolt did reveal the diverse range of threats that existed for any Norman king of England; from Denmark whose rulers still harboured ambitions of emulating Cnut, from France whose rulers feared a Duke of Normandy that ws also a king in England , and not least from his own Norman followers who frequently had ambitions of their own.
1William Fitz-Osbern had been one of William's closest supporters, who together with Odo of Bayeux had been effectively entrusted with the government of England whilst William was away in Normandy in the years immediately after the conquest before Fitz-Osbern's death in 1071.
2 Waltheof was the son of Sigurd Bjornson who had been made earl of Northumberland by Cnut and was descended on his mother's side from the long line of Anglo-Saxons who had held the Lordship of Bamburgh. Waltheof had also supported two previous revolts against William in 1069 and 1072, the latter despite having married William's niece.
3 One can only assume that the difference in treatment was down to the fact that Roger of Breteuil was Norman whereas Waltheof wasn't. Or perhaps it was simply a case of three strikes and out for poor Waltheof.
Sourced from the Historia Regum Anglorum et Danorum by Simeon of Durham and the Anglo-Saxon Chronicle (Michael Swanton translation, Phoenix Press 2000) together with The Normans in South Wales 1070-1171 by Lynn H. Nelson (University of Texas Press, 1966) and The Normans by David C Douglas (Folio, 2002).