Saadia Gaon

Saʻadiah ben Yosef Gaon (882/892 – 942) was a Jewish religious scholar and philosopher.
He was born in al-Fayyūm, Egypt. When he was 28, he left Egypt and his wife and two sons, and traveled to Babylonia. There, he helped schools in many Jewish communities. After a while, he left Babylonia because he was not happy with the government.
As a religious scholar, he translated the Bible into Arabic and wrote many commentaries on it. He also wrote the first Hebrew dictionary and grammar dictionary, and many books on Talmudic law. One of his famous books is called "Kitāb al-amānāt wa al-iʿtiqādāt" ("Book of Beliefs and Convictions").
He died at the age of 63, in Baghdad.