The English economy was fundamentally agricultural, depending on growing crops such as wheat, barley and oats on an open field system, and husbanding sheep, cattle and pigs. In the late Anglo-Saxon period many peasants moved away from living in isolated hamlets and instead came together to form larger villages engaged in arable cultivation. Agricultural land became typically organised around manors, and was divided between some fields that the landowner would manage directly, called demesne land, and the majority of the fields that would be cultivated by local peasants. These peasants would pay rent to the landowner either through agricultural labour on the lord's demesne fields or through rent in the form of cash and produce. By the 11th century, a market economy was flourishing across much of England, while the eastern and southern towns were heavily involved in international trade. Around 6,000 watermills were built to grind flour, freeing up labour for other more productive agricultural tasks.