Essex is one of the larger counties and originated as a kingdom. Its southern boundary is the Thames, the Stour separates it from Suffolk, and the Stort and the Lea from Hertfordshire and Middlesex to the west. For many centuries the marshes along the Lea valley and dense forests around Epping and Waltham protected it from interference. Cunobelinus moved the capital of the Catuvellauni from Verulamium to Colchester, subduing the Trinovantes before Caesar's invasion. The Romans took over the site and made it the provincial capital, Camulodunum, sacked in Boudicca's rebellion in ad 61. In the 5th cent. the area fell to the Saxons, moving up the coastal creeks, and a kingdom of the East Saxons was in existence by the early 7th cent. It maintained a somewhat precarious existence, sometimes trying to extend its influence into Middlesex, Kent, and Surrey, sometimes trying to hold at bay the superior forces of Mercia and Wessex. Mellitus was appointed bishop of London in 604 with the duty of converting the East Saxons and made some progress, but the area lapsed into paganism until mid-century. By the 9th cent. Essex had become a client state, first of Mercia, then of Wessex. In the late 9th cent. it was overrun by the Danes and allotted to them at the peace of Wedmore in 878. Danish settlement was not heavy, however, and the region was used mainly as a base, with camps at Maldon and at Mersea. It was reconquered by Edward the Elder. By the time Cnut took the whole kingdom, in the early 11th cent., Essex was emerging as a shire, with roughly its present dimensions. The county town was Chelmsford rather than Colchester, perhaps because it was more central.

For centuries Essex remained a rural county and something of a backwater. It had no mineral resources and its harbours were shallow. It was on no great national route, though the roads to Norwich and Ipswich brought some traffic. It could have been of strategic importance in relation to London but few invasion forces ventured up its muddy creeks. Colchester remained a sizeable town, the centre for a vigorous cloth trade, and with a reputation for oysters, but most of the other towns—Saffron Walden, Thaxted, Braintree, Romford, Waltham Abbey, Dunmow, Halstead, and Ongar—were of only local importance. Chelmsford, the shire town, was unusual in having no parliamentary representation, though Maldon, Harwich, and Colchester had two members apiece. Harwich profited from the Hanoverian connection in the 18th cent. to build up its position as a port for the continent. The shire provided London with fresh vegetables, particularly potatoes, but for many years the marshes remained a barrier to urban expansion. As late as 1907, the Victoria County History could write that Essex was ‘one of the purely agricultural counties of England, depending almost entirely upon tillage for its economic prosperity’.

The chief characteristic of the shire was religious nonconformity. Proximity to the continent made for easy access to reforming ideas in the Tudor period and the Essex towns provided a number of protestant martyrs during Mary's reign. Its puritan sympathies made it come down heavily in the 1640s for Parliament against the king and it saw little fighting, save for the siege of Colchester during the second civil war in 1648, which ended with the two royalist commanders being shot after surrendering. In 1698 Celia Fiennes noted that Colchester was ‘a town full of dissenters, besides Anabaptists and Quakers’.

Economic transformation came in the later 19th cent. with the overflowing of London into the old hundred of Becontree, first along the docks of the north bank of the Thames, then following the railway from Shoreditch to Romford in 1839, which built an important junction and repair works at Stratford. Dockers and railwaymen replaced farmers in the streets of south-west Essex. In 1801, Dagenham, Barking, Ilford, Walthamstow, East and West Ham were still separate villages or small towns. But for a time the increase in population was the fastest in the whole country. West Ham had fewer than 5,000 inhabitants in 1801 but 267,000 in 1901, dwarfing the county town, which had 13,000. While the population of Becontree hundred in the south-west rose from 21,000 to 650,000 that of Dunmow hardly changed and Freshwell hundred in the north actually declined. The taste for sea-bathing gave prosperity to Southend, which became Londoners' favourite resort: from the 1820s paddle-steamers brought day trippers, the pier was opened in 1830, extended in 1889, and the rail link in 1856 brought more: by 1991 its population was 153,000. The arrival of the Ford Motor Company at Dagenham in 1929 created a great new borough. Though suburban growth declined after the Second World War, the new towns at Harlow and Basildon and the airport at Stansted kept numbers increasing, while Epping, Braintree, and Chelmsford became commuter towns, disgorging into Liverpool Street. By 1991, Essex, with a population of 1,400,000, was third only to Hampshire and Kent among counties. In the 1980s the concept of ‘Essex man’, upwardly mobile, fast-driving, Tory-minded, brought the shire back into national consciousness. The recommendations of the Banham commission report on local government (1994) were implemented, Essex retaining county status, and Southend constituting a unitary authority.

J. A. Cannon