Towns and trade
England's cities and towns were evolving rapidly in the 12th and 13th centuries. Urban populations were growing, commercial life was expanding, and the complex structures of urban administration were beginning to emerge. In London, the only large city in England, networks of craftsmen, tradesmen and shopkeepers supported a thriving urban culture and the River Thames was busy with merchant traffic. The city jealously guarded the extent of its self-governance and its financial freedoms.
Only three clauses in Magna Carta are still valid today, one of which declares that London and all other cities, boroughs, towns and ports shall enjoy their ancient liberties and customs.
In 1215 a number of other clauses in the charter protected the interests of traders. Fish-weirs were to be removed from rivers because they impeded navigation and trade, particularly on the Thames and Medway. National standard measures for wine, ale, corn and cloth were introduced and foreign merchants were guaranteed the right to enter and leave the country and to enjoy freedom of movement within it, in accordance with ancient customs.