The name Essex originates in the Anglo-Saxon period of the Early Middle Ages and has its root in the Anglo-Saxon (Old English) name Ēastseaxe (“East Saxons”), the eastern kingdom of the Saxons who had come from the continent and settled in Britain (cf. Middlesex, Sussex and Wessex) during the Heptarchy. Originally recorded in AD 527, Essex occupied territory to the north of the River Thames, incorporating all of what later became Middlesex (which probably included Surrey) and most of what later became Hertfordshire. Its territory was later restricted to lands east of the River Lea.
Colchester in the north-east of the county is Britain’s oldest recorded town, dating from before the Roman conquest, when it was known as Camulodunum and was sufficiently well-developed to have its own mint. In AD 824, following the Battle of Ellandun, the kingdoms of the East Saxons, the South Saxons and the Jutes of Kent were absorbed into the kingdom of the West Saxons, uniting Saxland under King Alfred’s grandfather Ecgberht. Before the Norman conquest the East Saxons were subsumed into the Kingdom of England. After the Norman conquest, Essex became a county.