Colchester is claimed to be the oldest recorded town in Britain on the grounds that it was mentioned by Pliny the Elder in AD 77. Its Celtic name was Camulodunon, meaning 'the fortress of (the war god) Camulos'. Following the Roman conquest of Britain in AD 43, a Roman legionary fortress was established and the name Camulodunon was modified to the Roman spelling of 'Camulodunum'. Camulodunum served as the first Roman capital of Britain, but was attacked and destroyed during Boudica's rebellion in AD 61. Sometime after the destruction, London became the capital of the province of Britannia but it would seem that the council of the provincial natives still met at Colchester, where the Temple to the Divine Claudius served as the seat of this council. Later, when the Roman frontier moved north (c. AD 49), Camulodunum became a colonia known as Colonia Claudia Victricensis. In 2004 Colchester Archaeological Trust discovered the remains of a Roman Circus (chariot race track) underneath the Garrison in Colchester, a unique find in Britain.

Medieval Colchester's main landmark is Colchester Castle, which is an 11th century Norman keep, and built atop the vaults of the old Roman temple. There are notable medieval ruins in Colchester, including the surviving gateway of the Benedictine abbey of St. John the Baptist (know locally as "St. John's Abbey”), and the ruins of the Augustinian priory of St. Botolph (known locally as “St. Botolph's Priory").

In 1189, Colchester was granted its first Royal Charter by King Richard I (Richard the Lionheart.) The charter was granted at Dover with the King about to embark on one of his many journeys away from England. The borough celebrated the 800th anniversary of its charter in 1989.[3]

Between 1550 and 1600, a large number of weavers and clothmakers from Flanders emigrated to Colchester and the surrounding areas. They were famed for the production of Bays and Says cloth. An area in Colchester town centre is still known as the Dutch Quarter and many buildings there date from the Tudor period. During this period Colchester was one of the most prosperous wool towns in England. The old Roman wall runs along Northgate Street in the Dutch Quarter.