Berkhamsted was first mentioned in 970 CE and was recorded as a burbium (ancient borough) in the Domesday Book in 1086. Archeology traces a settlement from Neolithic times, through the Bronze Age, the Iron Age, the Roman Occupation to the Norman Conquest. During the Middle Ages the town of Berkhamsted was a busy wool trading centre. The oldest-known extant jettied timber-framed building in Great Britain, built between 1277 and 1297, survives in the 21st century as a shop on the town's high street.

Prehistory

Neolithic, Bronze Age, Iron Age and Roman artefacts show that the Berkhamsted area of the Bulbourne Valley has been settled for over 5,000 years. The discovery of a large number of worked flint chips provides Neolithic evidence of on-site flint knapping in the centre of Berkhamsted. Several settlements dating from the Neolithic to the Iron Age (about 4500–100 BC) have been discovered south of Berkhamsted. Three sections of a late Bronze Age to Iron Age (1200–100 BC) bank and ditch, wide by high and known as Grim's Ditch, are found on the south side of the Bulbourne Valley. Another Iron Age dyke with the same name is on Berkhamsted Common, on the north side of the valley.

In the late Iron Age, before the Roman occupation, the valley would have been within Catuvellauni territory. The Bulbourne Valley was rich in timber and iron ore. In the late Iron Age, a area around Northchurch became a major iron production centre, now considered to be one of the most important late Iron Age and Roman industrial areas in England. Iron production led to the settlement of a Roman town at Cow Roast, about northwest of Berkhamsted. Four Roman first century AD iron smelting bloomeries at Dellfield ( northwest of the town centre) provide evidence of industrial activity in Berkhamsted. Production ceased at the end of the Roman period. Other evidence of Roman-British occupation and activity in the Berkhamsted area, includes a pottery kiln on Bridgewater Road. The town's high street still follows the line of the Roman-engineered Akeman Street, which had been a pre-existing route from St Albans (Verulamium) to Cirencester (Corinium).

Roman period The High Street is on a pre-Roman route known by its Saxon name: Akeman Street. During Roman occupation the countryside close to Verulamium was subdivided into a series of farming estates. The Berkhamsted area appears to have been divided into two or three farming estates, each including one or more masonry villa buildings, with tiled roofs and underfloor heating. The remains of a villa were found close to the river in 1973 in the adjacent village of Northchurch. The oldest building, made of timber, was built in AD 60, rebuilt using stone in the early 2nd century, and enlarged to a ten-room building around AD 150. The house may have been empty for a period, reoccupied in the 4th century, and abandoned in the late 4th or early 5th century. A Roman-British villa, dyke, and temple were found NNW of the castle, near Frithsden, at the edge of the Berkhamsted Golf Course. Excavations in 1954 revealed masonry foundations and tesserae floors. Together, the villa, dyke and temple form a unique complex, suggesting occupation in the late Iron Age and Roman period. Two flint and tile walls from a Roman building were found north of Berkhamsted Castle in 1970. The construction of the castle's earthworks in the Middle Ages may have damaged this building.

Anglo-Saxon settlement

The earliest written reference to Berkhamsted is in the will of Ælfgifu (died AD 970), queen consort of King Eadwig of England (r. 955–959), who bequeathed large estates in five counties, including Berkhamsted. The location and extent of early Saxon settlement of Berkhamsted is not clear. Rare Anglo-Saxon pottery dating from the 7th century onwards has been found between Chesham Road and St John's Well Lane, with water mills near Mill Street in use from the late 9th century, show that an Anglo-Saxon settlement existed in the centre of modern-day Berkhamsted. The nearest known structural evidence of the Anglo-Saxon period are in the south and west walls of St Mary's Northchurch, to the north-west of modern Berkhamsted. The church may have been an important minster, attached to a high status Anglo-Saxon estate, which became part of the medieval manor of Berkhamsted after the Norman conquest..

The parish of Berkhamsted St Mary's (in Northchurch) once stretched from the hamlet of Dudswell, through Northchurch and Berkhamsted to the former hamlet of Bourne End. Within Berkhamsted, the Chapel of St James was a small church near St John's Well (a 'holy well' that was the town's principal source of drinking water in the Middle Ages). The parish of this church (and later that of St Peter's) was an enclave of about surrounded by Berkhamsted St Mary's parish. By the 14th century the adjoining village of "Berkhamsted St Mary" or "Berkhamsted Minor" name had become "North Church", later "Northchurch", to distinguish the village from the town of Berkhamsted.

1066 and the Domesday survey

Following the defeat of King Harold by William the Conqueror at the Battle of Hastings, the Anglo-Saxon leadership surrendered to the Normans at their encampment at Berkhamsted as recorded in the Anglo-Saxon Chronicle. From 1066 to 1495, Berkhamsted Castle was a favoured residence of royalty and notable historical figures, including King Henry II, Edward the Black Prince, Thomas Becket and Geoffrey Chaucer. In the 13th and 14th centuries, the town was a wool trading centre, with a busy local market. The oldest-known extant jettied timber-framed building in Great Britain, built between 1277 and 1297, survives as a shop on the town's high street.

The Anglo-Saxons surrendered the crown of England to William the Conqueror at Berkhamsted in early December 1066. After William defeated and killed Harold II at the Battle of Hastings in October, he failed in an attempt to capture London from the south. William led his army around London, crossing the River Thames at Wallingford, "laying waste" while travelling through southeast England. At Berkhamsted, he received the surrender of Edgar the Ætheling (heir to the English throne), Archbishop Ealdred, Earl Edwin, Earl Morcar and the leaders of London. It is not known why the town was chosen as the meeting place, except that it was in a defensive location north-west of London. William was crowned in Westminster Abbey on Christmas Day, 1066. After his coronation, William granted the "Honour of Berkhamsted" to his half-brother, Robert, Count of Mortain, who after William became the largest landholder in the country. Robert built a wooden fortification that later became a royal retreat for the monarchs of the Norman and Plantagenet dynasties.

According to the Domesday Book, the lord of Berkhamsted before the Norman conquest was Edmer Ator (also referred to as Eadmer Atule), thegn of Edward the Confessor and King Harold. The Domesday survey records that there was enough land for 26 plough teams, but only 15 working teams. There were two flour mills (Upper and Lower Mill), woodland for 1,000 pigs, and a vineyard. The total population was calculated to be either 37 or 88 households; the families included 14 villagers, 15 smallholders, 6 slaves, a priest, a dyke builder (possibly working on the earthworks of the castle) and 52 burgesses. Some historians have argued that the number of 52 burgesses in Berkhamsted was a clerical error, as it is a large number for a small town. Berkhamsted was described in the Domesday Book as a burbium (ancient borough) in the Tring Hundred. Marjorie Chibnall argued that Robert, Count of Mortain intended Berkhamsted to be both a commercial and a defensive centre; while John Hatcher and Edward Miller believed that the 52 burgesses were involved in trade, but it is unknown if the burgesses existed before the conquest.

Royal medieval castle (11th to 15th centuries)

Berkhamsted Castle is a (now ruined) motte-and-bailey Norman castle. Radiocarbon dating of organic remains from within the motte indicates that it was probably built post-1066 (a dyke builder is recorded in the town at the time of the Domesday Book). The castle was a high-status residence and an administrative centre for large estates (including the Earldom of Cornwall). Through the High and Late Middle Ages the close proximity of the royal castle and court helped fuel Berkhamsted's growth, prosperity and sense of importance. It created jobs for the local population, both within the castle itself and also, for example, in the large deer park. and in the vineyard, which were maintained alongside the castle..

After Robert, Count of Mortain, the castle passed to his heir William, who rebelled against Henry I and lost the castle to the king. In 1155 Henry in turn gave it to his favourite Thomas Becket, who held it till 1165. Becket was later alleged to have spent over £300 on improvements to the castle, a claim that led Henry to accuse him of corruption and may have contributed to his downfall. Henry II extensively used the castle, making it one of his favourite residences. Both King Richard I and King John gave the castle to their queens, Berengaria of Navarre and Isabella of Angoulême, respectively. In King John's reign, Geoffrey Fitz Peter (c. 1162–1213), Earl of Essex and the Chief Justiciar of England (effectively the king's principal minister) held the Honour and Manor of Berkhamsted from 1199 to 1212. During his time in the castle he was responsible for the foundation of the new parish church of St Peter (the size of which reflects the growing prosperity of the town); two hospitals, St John the Baptist and St John the Evangelist (one of which was a leper hospital), which survived until 1516; and for the layout of the town.

Following the signing of Magna Carta (1215), King John's reneging on the royal charter, the castle was besieged during the ensuing civil war, known as the First Barons' War, between John and barons supported by Prince Louis (the future Louis VIII of France), the French laid siege to Berkhamsted Castle (only a quarter of a mile from the town centre) in late December 1216. The queen's constable of the castle was the German Walerand Teutonicus.

<blockquote> After reducing the castle of Hertford, Louis marched on St Nicholas's day (6 December) to the castle of Berkhamsted and surrounded it with his engines of war. Whilst the English barons, after pitching their tents, were employed in setting them in order, the knights and soldiers of the garrison made a sally, seized the baggage and conveyances of the barons and gained possession of the standard of William de Mandeville with which they returned to the castle, regretting that they could do no further injury to them. On the same day, whilst the barons were sitting at table, the knights and soldiers of the garrison again made a sally, and, in order to put the barons in confusion, they carried before them the standard which they had taken a short time before, and thought to come on them unawares, but the latter were forewarned of this, and drove them back to the castle. When the following day dawned Louis ordered the petrarie (stone-throwing machines) and other engines of war to be erected around the city, which being done, they kept up a destructive shower of stones: but Waleran, a German, well tried in warfare, made a brave resistance against them and caused great slaughter amongst the excommunicated French.</p>—The contemporary chronicler, Roger of Wendover, based at St Albans abbey, 12 miles from Berkhamsted, describing the siege</p></blockquote>