6No one knows for certain when Bristol was founded. What we do know is that for the last 1,000 years and more it has been at the centre of national and international history, and was the first provincial borough to be upgraded to county status in 1373. From its earliest days Bristol's prosperity was linked to its port, especially with the importation of wine and tobacco and its involvement with the slave trade. Explorers sailed from Bristol on epic voyages and discovered new lands. For many years Bristol was the second or third largest English city. In recent times its economy has been built on the aerospace industry and the construction of Concorde, the world's first supersonic aircraft.