Masterpieces of religious architecture and important intellectual centres in the Middle Ages, the monasteries of Haghbat and Sanahin in the northern province of Lori were the first sites in Armenia to be included in the UNESCO World Heritage List in 1996. They were chosen as sites heritage of humanity because they represent the pinnacle of Armenian religious architecture, whose original style blends elements of Byzantine eclectic architecture and the traditional architecture of the Caucasus region. Both monasteries were founded in the 10th century. Between the 10th and 13th centuries, the monasteries of Haghpat and Sanahin were enlargened to include more than 20 churches and chapels, four annexes, mausoleums, bell towers, academic buildings, libraries, refectories, tunnels, bridges and other monumental structures. In these monasteries, the humanities, sciences and medicine were studied, treaties were written and miniatures were painted.