qnli question: WHen did the Piast dynasty appear? sentence: The Period of Division from, A.D., 1138 – A.D., 1314, which included nearly 200 years of feudal fragmentation and which stemmed from Bolesław III's division of Poland among his sons, was the genesis of the social structure which saw the economic elevation of the great landowning feudal nobles (możni/Magnates, both ecclesiastical and lay) from the rycerstwo they originated from.