From that date just about anything would be made from iron. Iron wheels and rails for them to run on, iron pots, pipes, boats and even iron coffins.
Darby's family were not just innovators, they had a marketing gene as well.
And to prove the versatility of the material, Darby's grandson built an iron bridge across the Severn.
In 1779, there was no knowledge of welding and the bridge used woodwork joints. It rapidly became world famous. Records show that people came from America, France, Belgium, Prussia, Sweden, Poland and Venice to see the wonder of the age. The Tontine hotel was built nearby to accommodate the visitors and the town of Ironbridge gradually grew around it.
Through the Victorian era the heavy industry declined, but the area's reputation did not. The Darbys' Coalbrookdale works was by this time producing decorative metalwork of intricate beauty. Two miles downstream, the Coalport chinaworks was exporting its wares across the world. And on the Severn's southern bank, the Jackfield factories were producing tiles and architectural ceramics.
But by 1920s the whole area was in deep decline. The pits of the Shropshire coalfield would last a few more years, but the Coalport china factories closed in 1926 and the Coalbrookdale works had shrunk down to a fraction of its former self.
The slow slide into honourable obscurity was halted in 1963, when the government designated the whole area as a new town. Named Telford, after the 18th century engineer, Thomas, who built roads and canals in the area, the new town was centred on the old mining villages of Dawley and Madeley.
To the north it enveloped the market town of Wellington, and its southern boundary was the Gorge, by now largely derelict.
Forty years later the changes are dramatic. Huge estates and massive inward investment have brought people and jobs to the town. The Darbys' successors still make iron goods, in the form of the popular Aga cooker. The industrial heritage is in the care of the Ironbridge Gorge Museum Trust, a charity that has cannily used every grant to ensure that future generations could come and see how their forefathers worked and lived.