His father, Isaac ben Ezra, was a wealthy and learned Jew of Jaén. Hasdai acquired in his youth a thorough knowledge of Hebrew, Arabic, and Latin, the last-named language being at that time known only to the higher clergy of Spain. He also studied medicine, and is said to have discovered a panacea, called "Al-Faruk". Appointed physician to Caliph Abd-ar-Rahman III (912-961), he, by his engaging manners, knowledge, character, and extraordinary ability, gained his master's confidence to such a degree that he became the caliph's confidant and faithful counselor. Without bearing the title of vizier he was in reality minister of foreign affairs; he had also control of the customs and ship-dues in the port of Córdoba. Hasdai arranged the alliances formed by the caliph with foreign powers, and he received the envoys sent by the latter to Córdoba. In 949 an embassy was sent by Constantine VII to form a diplomatic league between the hard-pressed Byzantine empire and the powerful ruler of Spain. Among the presents brought by the embassy was a magnificent codex of Pedanius Dioscorides' work on botany, which the Arabic physicians and naturalists valued highly. Hasdai, with the aid of a learned Greek monk named Nicholas, translated it into Arabic, making it thereby the common property of the Arabs and of medieval Europe.