Many histories would have you believe that Britain's royal history began with William, although his claim on the English throne was tenuous. He maintained that Edward the Confessor had promised him the succession as far back as 1051 during a period when Edward's relationship with Earl Godwin was low and Edward was looking for support. The connections between the Saxon and Norman royal families extended back to Athelred the Unready who had married Emma the sister of William's grandfather, Richard 11 of Normandy. William was the son of Edward the Confessor's first cousin. Researchers have been unable to find any evidence of Edward's promise, at least amongst English documents, and its only provenance is amongst the Norman chronicles. William was later able to exact support for the claim from Harold Godwinson, earl of Wessex, who was at William's court in 1065, and the Bayeux Tapestry shows Harold offering fealty to William. Hence when Edward died in 1066 and Harold was crowned as king, William regarded him as a usurper and prepared to invade.

William had already demonstrated his strength as a commander and soldier. His life was one of almost constant warfare as he carved out for himself a position as one of the most powerful and, when necessary, ruthless rulers of his day. He had succeeded to the duchy of Normandy in 1035 when just seven or eight years old. His father had died while on a pilgrimage when only 27. His mother, Herleva or Arletta, was Robert's mistress. She was the daughter of a local tanner and, legend says, Robert spied upon her while she washed clothes at the river. During William's minority there was much rivalry at the Norman court as the aristocracy struggled for power. Three of William's guardians were assassinated and the young duke knew he needed to assert his authority as soon as he was able. That opportunity came in 1047 when his cousin, Guy of Brionne, rebelled and claimed the duchy. Guy had considerable support and William needed the help of Henri I of France to win the day after a tightly fought battle. This gave William his authority but it also imprinted upon him a streak of ruthlessness which caused him to retaliate viciously against anyone who challenged him.

William's authority increased when he married Matilda, the daughter of Baldwin V, count of Flanders, a powerful ruler whose acceptance of William as a suitable son-in-law showed that William had risen above the trials of his youth. William may also have seen in Matilda a further link with his claim on the throne of England, as she was seventh in line from Alfred the Great. The pope apparently opposed this marriage for some years on grounds of an earlier betrothal by Matilda, but it finally received his blessing in 1059.

During the decade of the 1050s William continued to consolidate his power, even to the point of incurring the enmity of his former ally, Henri I of France. William succeeded in rebuffing all attempts to invade Normandy and by 1062 had himself invaded Maine, on almost the same pretext as he would invade England four years later - that Herbert, count of Maine, had promised William the county if he died without heirs. William became count of Maine in 1063. William's other conquests meant that he had support from the surrounding powers of Anjou and Brittany, whilst the new king of France, Philippe 1, was under the protection of William's father-in-law, Baldwin. This meant that when William prepared to invade England in September 1066 he was able to draw not only upon his own resources within Normandv, but upon those of his allies.

Nevertheless, this did not make William's conquest of England a certainty. He was up against one of the most aggressive armies of Europe under the command of Harold Godwinson. Harold's misfortune was that he had to face two invasions within one month. Harold's men already weakened by defeating the army of Harold Hardraada of Norway at Stamford Bridge on 25 September, faced a quick march back to fight William who had landed at Pevensey on 28 September. William took advantage of Harold's absence to develop his defences near Hastings and by pillaging the local farmsteads and hamlets. By so doing William succeeded in drawing Harold toward him, whereas Harold's opportunity for success lay in drawing William away from his fleet and its supplies. The two armies met at Senlac Hill (now Battle), near Hastings, on 14 October 1066. Had Harold's army not been weakened he may well have won, but they were overpowered by William's cavalry. The Saxon army submitted after the death of Harold and his brothers.

For the next two months William's army moved strategically around the Kentish coast taking a circular route to London and seeking the submission of the English en route. They burned Dover, and laid waste to much of Surrey. The English, in the meantime, had elected Edgar the Atheling as their new king, but he was only a boy of thirteen or fourteen, and unable to muster any forces to retaliate against William. The citizens of London prevented William crossing the Thames, so he sacked Southwark and moved west, crossing the Thames at Wallingford. Edgar submitted at Berkhamstead and the Normans then approached London from the north. Ludgate was opened to the invader by a collaborator and, in the Battle of Ludgate Hill, countless Londoners were slain. William was crowned in Westminster Abbey on 25 December 1066, the ceremony conducted by Ealdred, archbishop of York. Cries of support from the Normans present were interpreted as an English rebellion and the guards promptly attacked the Saxons and set fire to nearby houses. William himself had to quell the panic. His reign began with terror and would remain a reign of terror for twenty years.

Although William was to style himself as king of England not all of England had accepted him as king. His dominion was primarily in the south, covering all of the old kingdoms of Wessex, Kent, Sussex and Essex, and stretching someway into Mercia. The powerful earls of Mercia and Northumbria, the brothers Edwin and Morcar, believed that William's design was only to conquer Wessex and accepted him as king within that domain, pleased that he had overthrown the Godwin family. They even hoped they would be accepted as kings in their territories. This short-sightedness sealed the fate of England, for had the brothers united their armies with those elsewhere in England and faced William before he became established, he might still have been defeated, but the old rivalries between Saxon families became their downfall and isolated rebellions were soon put down with the viciousness with which William became renowned.

William remained in England for three months after his coronation, during which time he appointed a wide range of Norman officials, and despatched the army to plunder the churches in order to pay his army. When he returned to Normandy in late February 1067 he took with him the most likely candidates to lead any rebellion in England, Edgar the Atheling, Stigand, the archbishop of Canterbury, and the earls Edwin and Morcar. During his absence in Normandy, where William displayed the spoils of his conquest and made most of his fame, his half-brother Bishop Odo endeavoured to impose Norman rule in England, but with minimal success. An attempted invasion by Eustace, count of Bolougne, who was Edward the Confessor's brother-in-law, was soon repelled, but the general unrest in England, especially in the north and west, continued to grow. William returned in December 1067 and began his systematic conquest of England in earnest. He turned his attention first to the west, at Exeter, where Harold's mother had taken refuge. The town submitted after a siege of eighteen days. William was comparatively lenient to the townsfolk, though he exacted payment. He also ordered the building of a castle and established a Norman noble, Baldwin of Brionne, as the local custodian. This became Willam's approach over the next few years. As he advanced upon his conquests he would build a castle from which a Norman duke or earl would maintain the peace in that territory. Initially the castles were hasty constructions of wood upon a motte-and-bailey site. It was only later that he and his successors began the construction of massive stone castles at key sites. These castles became the image of Norman power created not to defend England but to dominate it. In total 78 castles were constructed by William's order, the most famous being the Tower of London. By March 1068 William felt sufficiently secure in the south to bring his wife, Matilda, over to England where she was crowned queen. She remained in England for a year, accompanying William on his tour of conquest. Their last son, the future Henry I was born at Selby in September 1068. She returned to Normandy in 1069 and remained there until her death in 1083.

It was during 1068 that William faced his first major opposition. Earls Morcar and Edwin rebelled, and Edgar the Atheling took refuge with Malcolm III Of Scotland - Malcolm married Edgar's sister Margaret the following year. The Saxons sought the support of the Welsh though clearly were not acting with any coherent plan for William was soon able to quash the rebellion by advancing on Warwick. William continued north, establishing castles at Nottingham and York. His original plans to govern northern England through the Saxon aristocracy now changed, as he believed Edwin and Morcar had forfeited their rights. From then on William redistributed the lands of the Saxons amongst the Norman and French aristocracy. The native English were not simply conquered, they were dispossessed. William was hated and despised by the English, but any attempt to display this feeling was countered by ruthless retaliation. When William returned briefly to Normandy in early 1069, faced with a revolt in Maine, the English attacked the Normans at Durham, killing many of them. They moved on to besiege the castle at York, but by then William had returned and he not only defeated the English but sacked the city.

The English resistance was far from over. Edgar the Atheling's followers joined forces with King Swein of Denmark. Swein had as much claim to the English throne as William, if not more. He was the nephew of Canute and maintained, like William, that Edward had named him as his successor. The English had learned to co-exist with the Danes. There had been Danish kings ruling parts of England for two centuries before Canute. The armies of Swein and Edgar, along with other northern rebels, recaptured York in September 1069. Again William marched on the north, this time destroying everything in his path. This harrying of the north was the most extreme example of despoiling and genocide that England has ever seen, and for which William was never forgiven by the English. He may have conquered them, but he never ruled them.

William succeeded in buying off the Danish force and they retreated in late 1070, after briefly returning for a second attempt. Pockets of resistance remained throughout the north, the west and especially in the Fenland of East Anglia, where the Saxon thane Hereward the Wake, perhaps the best known of the Saxon rebels, maintained the most ordered resistance to William. Hereward was joined by Earl Morcar whose brother, Edwin, had been treacherously murdered by his own men. William brought all his forces to bear upon the Isle of Ely where Hereward made the last major Saxon stand against the Norman might. William's power proved irresistible. Hereward escaped, but Morcar was captured and imprisoned, and other rebels were tortured and mutilated before their release.

The last to resist William was Edgar the Atheling who had fled back to the court of King Malcolm. In the summer of 1072 William marched into Scotland to demand that Malcolm cease aiding Edgar's insurrection. Malcolm agreed and, with the Peace of Abernethy, recognized William as his overlord. He also expelled Edgar from his court. Edgar, however, did not submit to William until 1074. By the end of 1072 William believed that his conquest of England was complete. Already he had replaced many of the Saxon officials with Normans, and these included the officials of the church. Probably his most significant appointment was of Lanfranc as archbishop of Canterbury. The Norman aristocracy were installed in lands across the length and breadth of England and their dominion established a feudal system in which all Saxons were increasingly treated as peasants. Although William had despoiled the land in order to subjugate the English, he had never intended to plunder it. Indeed, once he had established his authority he was keen for England to prosper so that he could benefit from the revenues. William returned to Normandy in 1072 and remained there for much of the next twelve years, needing to maintain his duchy against the opposition of the French and his former allies who were now fearful of his power. The administration of England was left in the hands of Richard Fitzgilbert and William de Warenne, two of William's most powerful barons.

William did not return to England for any significant period until 1085, when he brought over a massive army to defend the island against a planned invasion under Canute IV of Denmark. Canute, however, was murdered before the invasion began. William's restless army caused considerable hardship to the Saxons during this period. In addition William had to raise the land taxes in order to pay his sizeable army and this caused further disgruntlement. The problems that William had in knowing who owned what land and what its value was, so that he could levy the taxes, led to him ordering a major survey of England. The record of this survey, carried out with remarkable accuracy and speed during 1086, became known as the Domesday Book, and though its purpose was for William to ensure he had control over his taxes in England, the result is a rare and indispensable historical document. William, however, made little use of the document himself. He returned to Normandy at the end of 1086 where he became preoccupied with a local rebellion. In July 1087 William besieged the town of Mantes. As his horse jumped over a ditch William received an injury from the pommel of his saddle which ripped into his stomach. The wound became poisoned leading to peritonitis. William was carried back to Rouen in considerable pain. He lingered on for five weeks, and died in September. His body was returned to Caen for burial but apparently the tomb was not big enough - the king was a tall man, at least five feet ten inches. As a result, as the attendants forced the body into the tomb, the already decaying and swollen body burst open, letting out an intense smell of putrefaction that caused most to flee the site. Only a hardy few completed the burial.

William changed England irrevocably. His total domination had, within less than a generation, almost eradicated the Saxon aristocracy and imposed a feudal society run by a small handful of Normans. The language difficulties added further to the alienation, but perhaps the most significant difference was in the lifestyle. Although the Normans were descended from the Vikings, they no longer looked to the north as their ancestral home, unlike the Saxons whose inheritance was from northern Europe. The Normans had taken on the more sophisticated lifestyle of the French, which brought with it the power, grandeur and aloofness of an upper-class existence. William used England as his playground, establishing the New Forest in Hampshire for his hunting. He had no liking for the English or, for that matter, for England, seeing it only as a rich source of revenues. Although his harsh rule brought peace to England, where man was apparently able to travel without fear of crime, this was only because the English lived in much greater fear of revenge and retribution from their Norman overlords. It created a rift between the nobility and the common man which remained in Britain for centuries.

William was devoted to his wife Matilda, and was much saddened at her death. They had ten children. The eldest, Robert, succeeded William as duke of Normandy and count of Maine even though he had been in open rebellion against his father in his latter years. The second son, Richard, died in his twenties in 1081 while hunting in the New Forest. Two other sons, William and Henry, Succeeded William as kings of England. Of his six daughters, Adela became the mother of the future king Stephen.