The Chelmsford area has been occupied for a long time. There is evidence of Late Bronze Age settlements at both Springfield and Great Baddow.
The first township was established in Roman times in the Moulsham area, south of the River Can. This was roughly half way between London and Colchester and was known as Caesaromagus ("Caesar's market"). It was the site of a Roman fort which eventually spread alongside the London-Colchester road to become a government posting station. The township developed as building plots were added. At one time the town was fortified but it gradually declined and was abandoned shortly after the Romans left in 407 AD.
When they moved in the Saxons settled further to the north, around the Broomfield, Springfield and Waltham areas. The old Roman river crossing at Caesaromagus had become impassable because of flooding but eventually a ford was established. Tradition has it that this ford was controlled by a Saxon called Ceolmaer. (Spellings of his name vary.) The place became known as Ceolmaer's Ford, later corrupted to Chelmer's Ford and eventually to Chelmsford.
The modern Chelmsford had its root in Norman times, when the then Bishop of London had a bridge built to replace the ford and arranged for the first houses to be built in what is now the High Street. In 1199 the town was granted a charter enabling it to hold markets and the area again became an important stop on the road from London to Colchester. By the middle of the 13th century Chelmsford was the main centre for the administration of justice in Essex.
Chelmsford continued to prosper. King Edward VI's Grammar School ("KEGS") was founded in 1551 and still continues its work today.
There was great activity at the end of the eighteenth century. A new jail was built in 1777, the present Stone Bridge in 1787 and the Shire Hall in 1791. The canal to the seaside town of Maldon was opened in 1797. During the Napoleonic Wars Chelmsford became a barracks town.
The railway came to the town in 1843. In the second half of the nineteenth century a number of important manufacturing companies opened factories in Chelmsford, including most notably Marconis. A lot of this manufacturing was lost to the town in the last quarter of the twentieth century but a number of companies in the insurance and financial sectors set up offices.