A period of tolerance dawned for the Jews of the Iberian Peninsula. Their number was considerably augmented by immigration from North Africa in the wake of the Muslim conquest. Immigrants from North Africa and the Middle East bolstered the Jewish population and made Muslim Spain probably the largest centre of contemporary Jews. Especially after 912, during the reign of Abd al-Rahman III and his son, Al-Hakam II, the Jews prospered culturally, and some notable figures held high posts in the Caliphate of Córdoba. Jewish philosophers, mathematicians, astronomers, poets and rabbinical scholars composed highly-rich cultural and scientific work. Many devoted themselves to the study of the sciences and philosophy, composing many of the most valuable texts of Jewish philosophy. Jews took part in the overall prosperity of Muslim Al-Andalus. Jewish economic expansion was unparallelled. In Toledo, after the Christian reconquest in 1085, Jews were involved in translating Arabic texts to the romance languages in the so-called Toledo School of Translators, as they had been previously in translating Greek and Hebrew texts to Arabic. Jews also contributed to botany, geography, medicine, mathematics, poetry and philosophy.