The larger settlements grew into market towns, typically through the late Middle Ages. Farming and a cottage woollen industry developed during the reign of Henry VIII, but Rossendale's population only really expanded during the period of the Industrial Revolution. The population was 16,033 in 1801; in 1901 it had grown to 89,540 ("relevant censuses"). Its wet and damp climate are ideally suited to the development of watermills, and later to the mechanisation of the wool and cotton spinning and weaving industries in the 18th and 19th centuries. In the middle of the 19th century a felt industry developed, and from this the manufacturing of slippers so that footwear also became a major employer in the area.