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Born a Jew in Barcelona, I became a mathematician, astronomer philosopher...and also a Chief of Police.

A pupil of Rabbi Moshe haDarshan and a teacher of Abraham Ibn Ezra, I also dabbled by writing texts in astronomy and geography...and wrote papers on astrology, trigonometry and music.

I wrote all my works in Hebrew, making me the recognized pioneer in the use of the Hebrew language for scientific purposes.

I am most proud of my text Ḥibbūr ha-meshīḥah we-ha-tishboret ("Treatise on Measurement and Calculation"), which not only focuses on algebra and practical geometry, but also contains the first complete solution of the quadratic equation x2 - ax + b = 0 known in Europe.

My work influenced the work of Leonardo Fibonacci.

Using the geometric-mechanical method of indivisibles, I proved the area equation for any circle: S = LxR/2, where S is the area of the rectangle, L is the circumference of the circle, and R is the radius of the circle.

Answer: Abraham bar Ḥiyya (1070 1136 or 1145)