|The project investigated changes in the human and natural environments of the marshlands bordering the tidal river Thames and the Thames Estuary between 1250 and 1550. At the beginning of this period the marshlands had largely been drained and protected by banks or walls, so that they could be used for arable and pastoral farming. During the three centuries studied, however, many of these reclaimed marshes were flooded by the sea or by freshwater inundation. The causes were partly natural and partly human. Major flooding events may have become more common, and clusters of North Sea storm surges occurred, in which winds and tides combined to thrust large quantities of sea-water into the Thames Estuary, overwhelming flood defences. At the same time, declining population after c.1300, and associated agricultural recession, meant that it was no longer so profitable to defend the marshes against the sea. As a result, especially after the 1370s, many marshes flooded, and attempts to recover them were given up. Among the areas most affected were parts of the Barking, East Ham and Dagenham marshes, the Isle of Dogs, Erith and Lesnes marshes and the marshes around the mouth of the river Medway. In these and other locations fishing, fowling and the cutting of reeds and rushes replaced farming as the main sources of employment and income. Londoners complained about some of the effects of flooding, but may have benefited from the 'retreat' from the down-river marshes, which reduced the flood risk to Southwark, Bermondsey and other vulnerable suburbs.