The father of medieval Jewish philosophy, Saadia was born in Egypt and educated there and in Palestine. In 928 he was appointed head of the rabbinical academy of Sura, near Baghdad, but, much involved in the sectarian disputes of the time, he was exiled for a while before finally being reinstated. His principal philosophical work is the Book of Doctrines and Beliefs, modelled on the work of Islamic theologians but based upon Jewish rather than Islamic scripture. Saadia defends human knowledge against the attacks of scepticism, and attempts to prove the creation of the world. His division of the commandments of the Torah into those that are rational and those that are traditional or revealed was later rejected by Maimonides.