The first of the 2000 year old religious documents were found in 1947 in a cave near Qumran, about 20 kilometers east of Jerusalem. Scientists since have gathered more than 25,000 pieces of writing on skin and ancient paper in the caves and other sites in the Judean Desert. The University of Tel Aviv, the Israeli government and experts from Uppsala University in Sweden and Weill Cornell Medicine in New York City carried out DNA tests over seven years. They identified the kind of animal skins used for the documents. The finding will help experts to establish real scrolls from fakes. Many experts believe the scrolls were made by a small Jewish group called the Essenes. The Essenes had separated from the more traditional Jewish religion and were very secretive. However, other experts argue that several people from different groups wrote the Dead Sea Scrolls. Those experts believe the scrolls were gathered together and put in the cave to keep them safe during a time of conflict. The DNA tests show that the animal skin used for the writings was mainly from sheep common to the desert area. But, there were also some cow skin documents.