As early as the 12th century, some fields in England tilled under the open field system were enclosed into individually owned fields. The Black Death from 1348 onward accelerated the break-up of the feudal system in England. Many farms were bought by yeomen who enclosed their property and improved their use of the land. More secure control of the land allowed the owners to make innovations that improved their yields. Other husbandmen rented property they "share cropped" with the land owners. Many of these enclosures were accomplished by acts of Parliament in the 16th and 17th centuries.