Colchester was still a prosperous town in the early 1700's. Visitors commented favourably on its broad High Street, paved sidewalks and new brick houses. Hollytrees and The Minories, now a museum and art gallery respectively, are two of the surviving Georgian mansions that confirm the wealth and taste of the town's leading citizens in this period. By contrast, John Wesley, founder of the Methodist Church, who made several preaching visits to Colchester, encountered great poverty as well. The prison reformer John Howard was critical of the grim conditions he found in the castle, which was still in use as a gaol.
The famous local bay and say cloth industry went into terminal decline in the 18th Century. However, Colchester's roller coaster fortunes took another upward turn in the late 1700's when an agricultural boom in Essex brought new prosperity to the town's markets and trade. The end of the traditional cloth industry in Colchester and the rise of new agricultural trade was marked both physically and symbolically by the opening of a grand new corn exchange in 1820. It was on the site, at the western end of the High Street, formerly occupied by the Dutch Bay Hall.