As populations grew and the demand for food increased, long-term storage of grain became vital. With improved transport allowing for the movement of grain, it became possible to construct vast storage warehouses to hold shipped-in food stock. The Romans had an influx of around half-a-million tonnes of food from their harvests which would eventually be dispersed around the city population but this was stored within huge warehouse complexes built at Ostia and just outside Rome. A vast network of warehouses or 'horrea' were built along the embankment of the River Tiber in an area known as the Emporium district.
