The first dikes were low embankments of only a meter or so in height surrounding fields to protect the crops against occasional flooding. After about CE 1000 the population grew, which meant there was a greater demand for arable land but also that there was a greater workforce available and dike construction was taken up more seriously. The major contributors in later dike building were the monasteries. As the largest landowners they had the organization, resources and manpower to undertake the large construction. By 1250 most dikes had been connected into a continuous sea defense.