In the last third of the 1700s Barcelona was a city undergoing a major transformation. The regional specialization process that took place in Catalonia, and the intensification of exchange, generated spectacular economic growth and an unprecedented increase in population. The city of Barcelona tripled its population in just over seventy years; in 1787 it already had around 100,000 inhabitants. Immigration, both from the Pyrenean areas and from the proto-industrial areas of central Catalonia, the natural growth of the population, the intense process of urbanization, and the dynamism of the labour market explain the densification of the city and the rise in the price of rents.