The rise of West-Central Scotland must surely rank as the classic story of Scotland's economic history. The focus of activity is the Clyde, an extensive and sheltered maritime inlet well connected with the system of ‘western seaways’ which have been shown to be so crucial to an understanding of trade and migration in prehistoric and later times. Apart from its use for trade and commerce there were valuable natural resources in herring and salmon, and although medieval commerce was concentrated by law in the burghs fishing was open to all the coastal settlements. However, these advantages counted for little before the development of the Atlantic routes, conditioned by the colonisation of America and the removal of legal barriers to trade with English colonies by Scottish merchants in 1707, and before the technology of the industrial revolution had revealed tremendous possibilities which local entrepreneurs were ready to exploit. This transformation of regional potentials led not just to the dominance of the Clyde valley in Scottish economic affairs but to the emergence of Glasgow as the key city in this dynamic complex of industry and trade. ‘That the ecclesiastical burgh of Bishop Jocelin should attain such distinction would certainly have appeared incredible to the inhabitants of the older king's burghs of Rutherglen and Renfrew, and equally so to those of Dumbarton, the ancient and strategically situated capital of Strathclyde’. Yet by the end of the sixteenth century Glasgow had achieved greater taxable importance than her rivals in the west and was the second city in Scotland by 1670.