There has been coastal erosion in the area for thousands of years, though it was relatively sheltered until the Middle Ages by a series of offshore barrier islands or shoals made up of boulder clay. Rising sea levels and more intense sea storms from the 13th century onward very likely eroded these islands, increasingly exposing the Skegness coast to the tides. Records from the Middle Ages show that local people maintained sand banks as a form of sea defence; fines were levied for grazing animals on the dunes, which could weaken the defences. Skegness was flooded in 1525 or 1526, requiring the village to be rebuilt inland, and loss of land continued during the century. A clay embankment, Roman Bank, was built in the late 16th century and was followed in "c". 1670 by another closer to the sea (Green Bank), running from what is now North Shore Road to Cow Bank, following a line from St Andrew's Drive to Drummond Road. By the late 19th century, sands were accreting at Skegness; the retaining sea wall erected in 1878 was designed to support the resort town's seafront development rather than to protect it from the sea. Nevertheless, this wall largely saved the town during the 1953 flood, when only gardens, the amusements and part of the pier were damaged.