William the Conqueror
The brothers, Earl Edwin (of Mercia) and Earl Morcar (of Northumbria), had taken no part in the battle of Hastings. Florence of Worcester says they had "withdrawn themselves and their men from the conflict". This seems a somewhat harsh judgement, since the earls had suffered large losses, when they faced the full force of Harald Hardrada's invading army, at Fulford, less than four weeks previously. Indeed, according to William of Malmesbury, King Harold had instructed them to convey "the spoils of war" from Stamford Bridge to London, whilst he hastened to engage Duke William of Normandy. At any rate, when they heard of Harold's death, the brothers (noted by Florence of Worcester) sent their sister, Ealdgyth, Harold's wife, from London to safety in Chester. Manuscript D of the 'Anglo-Saxon Chronicle' reports that Ealdred, archbishop of York, and the burghers of London wanted to have Edgar (known as Edgar 'the Ætheling'), grandson of Edmund Ironside elected king. Edwin and Morcar agreed to fight for him, but then the plan seems to have descended into chaos:
"But the more prompt the business should ever be, so was it from day to day the later and worse; as in the end it all fared."
Florence of Worcester is rather more specific:
"But while numbers were preparing to go out to fight, the earls [Edwin and Morcar] withdrew their assistance and returned home with their army."
William of Malmesbury asserts that Edwin and Morcar:
"... solicited the citizens [of London] to raise one of them to the throne; failing, however, in the attempt, they had departed for Northumberland, conjecturing by a surmise of their own that William would never come thither. The other chiefs would have chosen Edgar, had the bishops supported them; but, danger and domestic broils closely impending, neither did this take effect."
Meanwhile, back at Hastings, Duke William had been waiting, apparently in expectation of receiving the submission of the English witan:
"... when he found that they would not come to him, he went up with all his force that was left and that came since to him from over sea, and ravaged all the country that he overran, until he came to Berkhamsted ..."
'Anglo-Saxon Chronicle' Manuscript D
According to the 'Carmen de Hastingae Proelio', William had spent a fortnight waiting in Hastings before "he directed his march towards Dover". William of Poitiers says that he "left a force at Hastings under an energetic commander", and that he paused at Romney, "which he punished at his pleasure for the damage they had inflicted upon some of his men, who had come there by mistake". Both the 'Carmen' and William of Poitiers agree that Dover was heavily fortified, but the 'Carmen' asserts that the "terrified" people of Dover came to submit to Duke William before he got there. William of Poitiers says that they "took fright and lost all confidence both in their natural and man-made defences and in their numerical strength". They were on the point of submitting when some Norman soldiers, "lusting for loot", torched the place (Note). The duke, magnanimously, made amends for his men's actions, and, having taken possession of Dover, spent eight days adding to its fortifications. The 'Carmen' says that Duke William turfed the inhabitants out of their homes and billeted his men in them. He was at Dover for a month, during which time "acceptable gifts" were received from various places as tokens of surrender - Canterbury having set the ball rolling by being first to pay tribute. William then "went to set up camp for himself elsewhere", and sent word to Winchester - demanding that they too pay tribute. Winchester was held in dower by Edith, widow of King Edward, and William "considered it would be dishonourable if he went to take away the seat thus granted her; he asked only an impost and a pledge". The queen and town magnates settled with William, and Winchester was left in peace. William then "directed his march to where populous London gleamed".
William of Poitiers claims that Edith: "... wanted the English to be ruled over by William whom king Edward her husband had adopted as a son and established as his heir ..."
In William of Poitiers' account, however, there was an outbreak of severe dysentery amongst the Norman forces at Dover. Leaving the sick behind, Duke William left Dover, and was soon met by representatives of Canterbury, who submitted to him. The following day the duke went to somewhere called "the Broken Tower", where he fell ill. Nevertheless, the advance continued towards London. English forces emerged from London, but were driven "back within the walls" by William's advance guard of five hundred knights. An approach to London from the south, across London Bridge, cannot have been a viable military option.
In the 'Carmen', London is described as being: "Protected on the left [i.e. north] side by walls, on the right side by the river, it neither fears enemies nor dreads being taken by storm."
William's knights burned the suburbs on the south bank of the Thames, and the duke struck westwards until he came to Wallingford.
William of Poitiers implies that Duke William crossed the Thames at least once ("crossed the Thames by ford and bridge") on his progress to Wallingford, but William of Jumièges suggests that the duke stayed on the south side of the Thames until he came to Wallingford, and crossed there. Incidentally, William of Jumièges has Duke William setting off for London on the morning after the battle of Hastings, and records no incident until the duke leaves "the high-road" and heads for Wallingford.
In William of Poitiers account, it was Archbishop Stigand of Canterbury ....
Stigand had been given this position (he also retained the see of Winchester) when his predecessor Robert of Jumièges had been outlawed, and fled, in 1052. The irregularity of these circumstances meant that his appointment was not recognised by Rome until 1058, and then only by the antipope Benedict X. When Benedict was deposed (by Pope Nicholas II, 1058-61), Stigand became, once more, persona non grata, but remained in office.
.... not Archbishop Ealdred of York, who, "with the support of the sons of Ælfgar [i.e. Edwin and Morcar] and other magnates", had tried to get Edgar the Ætheling elected king. Stigand now came to Duke William, at Wallingford, renounced Edgar and swore fealty to the duke. Both William of Poitiers and William of Jumièges have the duke proceed directly from Wallingford to London. Manuscript D of the 'Anglo-Saxon Chronicle', however, having reported no specific incident since William's departure from Hastings, says that, at Berkhamsted:
"... Archbishop Ealdred came to meet him, with Eadgar cild [Edgar the Ætheling], and Earls Edwin and Morcar, and all the best men from London [Note]; who submitted then for need, when the most harm was done. It was very ill-advised that they did not do so before, seeing that God would not better things because of our sins. And they gave him hostages and took oaths: and he promised them that he would be a faithful lord to them; though in the midst of this they [the Normans] plundered wherever they went."
Manuscript D proceeds directly to William's coronation. In William of Poitiers version of events, as soon as the duke was within sight of London, the city's magnates came to him and surrendered themselves and the city:
"After this, both the bishops and other magnates prayed him to take the crown, pleading that they were accustomed to serve a king and wished only for a king to be their lord."
After some hesitation (he was reluctant to have a coronation whilst England was still unsettled, and he would have liked to have had his wife crowned with him), Duke William agreed to accept the crown, and preparations for his coronation were started. William also sent a party to build a castle in the city - presumably the beginning of the Tower of London.
It is clear that not all the citizens of London were quite so ready to surrender as might be supposed form William of Poitiers and the 'Anglo-Saxon Chronicle'. William of Jumièges writes:
"... an advance-party of knights, on entering the city, found a large force of rebels determined to make a vigorous resistance. At once engaging them, the knights inflicted much sorrow upon London by the death of many of her sons and citizens. At length the Londoners, seeing that they could resist no longer, gave hostages and submitted themselves and all they had to their noble conqueror and hereditary lord."
In the story told by the 'Carmen' there is no mention of Wallingford or Berkhamsted (though there is the comment that William, during his progress to London, "laid waste by the hostile sword what he had not ravaged by fire"). There is, however, an account of William's capture of London. The duke's men encamped around the city walls - he himself took up residence in King Edward's hall at Westminster - siege engines were constructed, and the citizens of London were terrified. The leading magnate in London is named as Ansgar. There was a diplomatic exchange between William and Ansgar, in which the duke out-manoeuvred Ansgar, and the English magnates were left with little choice other than to renounce "the boy" (Edgar the Ætheling), surrender the city, and submit to William.
William was crowned, by Ealdred, at Westminster Abbey, on Christmas Day 1066. William 'the Bastard' had earned a new soubriquet: William 'the Conqueror'.
As part of the coronation ceremony, the English contingent were asked, by Ealdred, if William was acceptable as king. The same question was put to the French speakers by Bishop Geoffrey of Coutances. According to William of Poitiers, the shouts of assent which followed alarmed the guards outside. Fearing treachery, they torched the neighbouring buildings. Orderic Vitalis adds to this that the fire spread rapidly, the congregation fled: "Only the bishops and a few clergy and monks remained, terrified, in the sanctuary, and with difficulty completed the consecration of the king who was trembling from head to foot."
After his coronation, King William remained in London for some time, organising his government. William of Poitiers praises the king's justice and clemency. He is at pains to point-out the strict instructions the king gave to his magnates not to oppress the conquered English, and how he set taxation at a reasonable level. In contrast, Manuscript D of the 'Anglo-Saxon Chronicle' mentions, only, that King William imposed heavy taxation, whilst Manuscript E says that "men paid him tribute, delivered him hostages, and afterwards bought their land" (Add.01).
William also confiscated the holdings of those Englishmen who fell at Hastings. A writ of his to the abbot of Bury St.Edmunds states: "I give you to know that I will that Abbot Baldwin hand to me all the land which those men held who belonged to St.Edmund's soke and who stood in battle against me and there were slain."
"He [King William] left London and stayed for some days in a nearby place called Barking while certain fortifications were completed in the city to contain the restlessness of it's vast and savage population."
William of Poitiers
The embryonic Tower of London, to the east of the city, would have been part of the "certain fortifications" referred to by William of Poitiers, but, in all likelihood, they also included two other castles: Baynard's Castle, in the south-western corner, on the eastern bank of the river Fleet (near to modern day Blackfriars Station) and Montfichet Castle probably just to the north of Baynard's Castle.
Though Manuscript D of the 'Chronicle' reported that, the brothers, Earl Edwin of Mercia and Earl Morcar of Northumbria had already submitted to William at Berkhamsted, William of Poitiers says that it was actually whilst William was in Barking that the earls, along with "many other nobles and magnates", submitted to him. Possibly William of Poitiers confused Barking with Berkhamsted. At any rate:
"The king graciously accepted the oaths which they offered him, generously bestowed his favour upon them, restored to them all their possessions, and held them in great honour. Proceeding thence, he came to divers parts of the kingdom, arranging everything to his convenience and that of the inhabitants. Wherever he went all laid down their arms. There was no resistance, but everywhere men submitted to him or sought his peace ... The aetheling [Edgar] himself, whom after the fall of Harold the English had thought to make king, he endowed with wide lands and took into the closest circle of his affection ... Many English received by his liberal gift more than they had ever received from their fathers or their former lords. He placed capable castellans with ample forces of horse and foot in his castles, men brought over from France in whose loyalty no less than competence he could trust. He gave them rich fiefs in return for which they willingly endured hardship and danger. But to no Frenchman was anything given unjustly taken from an Englishman."
William of Poitiers
By the spring of 1067, William had sufficient confidence in his mastery of England to undertake a visit to Normandy. However, by way of insurance, he decided to take with him ("in honourable captivity", as Orderic Vitalis puts it) many "good men of England" ('ASC' MSD) whom he thought might inspire rebellion in his absence. Amongst these were Earls Edwin, Morcar (Add.02) and Waltheof, Edgar the Ætheling and Archbishop Stigand of Canterbury.  Note
"... in the month of March he returned to his native land after a success even greater than our pen can relate."
William of Poitiers
Rebellion & Retribution    
Symeon of Durham 'Historia Regum' by J. Stevenson
Orderic Vitalis 'Historia Ecclesiastica' by Marjorie Chibnall
'Anglo-Saxon Chronicle' by Rev. James Ingram/Dr. J.A. Giles
'Carmen de Hastingae Proelio' by Catherine Morton and Hope Muntz
William of Jumièges 'Gesta Normannorum Ducum' by R. Allen Brown
'The Chronicle of Florence of Worcester' edited and in part translated by Joseph Stevenson
William of Malmesbury 'Gesta Regum Anglorum' by Rev. J. Sharpe, revised by Rev. J. Stevenson
William of Poitiers 'Gesta Guillelmi ducis Normannorum et regis Anglorum' by Raymonde Foreville/R. Allen Brown