 The city's "Tobacco Lords" created a deep water port at Port Glasgow on the Firth of Clyde, as the river within the city itself was then too shallow.By the late 18th century more than half of the British tobacco trade was concentrated on Glasgow's River Clyde, with over of tobacco being imported each year at its peak.At the time, Glasgow held a commercial importance as the city participated in the trade of sugar, tobacco and later cotton.