Gnanou Diagou hailed from a
Catholic family from Pondicherry. He obtained his law degree from the Faculty of Aix in 1902. He served as president of the Pondicherry Bar Association from 1934. He was also a professor of Law at Pondicherry Law School. In 1911, he founded the Historical Society of Pondicherry. He was also known as historian of
French India. He translated Tamil texts into French. In 1942, he translated the
Tirukkural, an ancient Tamil classic, into French. ==Works==