Dr. William Draper in 'History of Intellectual Development of Europe': "During the period of the Caliphs the learned men of the Christians and the Jews were not only held in great esteem but were appointed to posts of great responsibility, and were promoted to the high ranking job in the government… He (Caliph Haroon Rasheed) never considered to which country a learned person belonged nor his faith and belief, but only his excellence in the field of learning."