Fish have been recognised as a major food source from the earliest times. Fishing was important to the earliest settlers in Scotland, around 7000 BC. At this stage, fishing was a subsistence activity, undertaken only to feed the fisher and their immediate community. By the medieval period, salmon and herring were important resources and were exported to continental Europe, and the towns of the Hanseatic League in particular. As the industry developed, "fishertouns" and villages sprang up to supply the growing towns and fishing became more specialised. The many religious houses in Scotland acted as a spur to fisheries, granting exclusive fishing rights and demanding part of their tithes in fish.