He was the son of Abdur Rahman III. Together with his father's reign, his reign (961-76) marked the Apogee of Muslim rule in Spain. He was also known as al-Hakam (judicious). He was a bibliophile and had a collection of 400,000 books. He was probably the best scholar among the Muslim Caliphs, as his marginal notes on certain manuscripts, proved. Dozy, the Dutch scholar mentioned about the level of education then in Spain that 'nearly everyone could read and write'.