text: History Although the kingdom of Essex was one of the kingdoms of the Heptarchy, its history is not well documented. It produced relatively few Anglo-Saxon charters and no version of the Anglo-Saxon Chronicle; in fact the only mention in the chronicle concerns Bishop Mellitus. As a result, the kingdom is regarded as comparatively obscure. For most of the kingdom's existence, the Essex king was subservient to an overlord – variously the kings of Kent, East Anglia or Mercia.
  Origin
  Saxon occupation of land that was to form the kingdom had begun by the early 5th century at Mucking and other locations. A large proportion of these original settlers came from Old Saxony. According to British legend (see ) the territory known later as Essex was ceded by the Celtic Britons to the Saxons following the infamous Treason of the Long Knives, which occurred  during the reign of High King Vortigern. Della Hooke relates the territory ruled by the kings of Essex to the pre-Roman territory of the Trinovantes. Studies suggest a pattern of typically peaceful co-existence, with the structure of the Romano-British landscape being maintained, and with the Saxon settlers believed to have been in the minority.
  The kingdom of Essex grew by the absorption of smaller subkingdoms or Saxon tribal groups. There are a number of suggestions for the location of these subkingdoms including:
  The Rodings ("the people of Hrōþa"),
  the Haemele, Hemel Hempstead
  Vange – "marsh district" (possibly stretching to the Mardyke)
  Denge
  Ginges
  Berecingas – Barking, in the south west of the kingdom
  Haeferingas in the London Borough of Havering
  Uppingas – Epping