By the end of the eighteenth century, Birmingham had become the hub of a highly integrated regional economy. The Black Country and the West Midlands as understood today should be regarded as the product of a transition towards spatial and economic integration which culminated towards the middle decades of the nineteenth century. Economic geographers argue that transportation innovations provide the key to regional growth and differentiation in the late eighteenth and early nineteenth centuries. Matthew Boulton and the other Birmingham manufacturers lobbied for a navigable link of more immediate value, namely one which would connect the town's industries to their fuel sources in the Black Country. The historians of Birmingham seem unconvinced of the case for an urban identity. The English agricultural writer Arthur Young visited Birmingham several times in the 1760s and 1770s, and in 1791 labelled it as 'the first manufacturing town in the world'.