Ralbag רלב"ג
Bible commentator, philosopher, mathematician and astronomer of Provence
Rabbi Levi ben Gershon lived in Provence, in Bagnols and Orange, a generation after the Meiri. He was among the most versatile minds of the Jewish Middle Ages: Bible commentator, philosopher, mathematician, astronomer and physician.
His chief philosophical work is «Milchamot HaShem», the Wars of the Lord, treating the immortality of the soul, prophecy, providence, the heavens and the creation of the world. Ralbag follows Aristotle further than most Jewish thinkers and reaches conclusions later authorities sharply rejected — some called the book «Wars against the Lord». Even opponents acknowledged his honesty and rigour.
In his Bible commentary he does something unusual: after expounding the text he lists «to'aliyot», the benefits — moral and practical lessons of the chapter — making the work a manual of conduct as well as an exposition.
His scientific legacy reached beyond the Jewish world. He invented the «Jacob's staff» for measuring angles between heavenly bodies, used by navigators into the age of discovery; his astronomical tables were cited by Latin authors, and a lunar crater bears his name.