Menahem ben Saruq מנחם בן סרוק

From Tortosa, born about 920; of a poor family, his father a teacher. Hasdai ibn Shaprut, a grandee of the Cordovan caliph, took him into his service—and Menahem wrote his letters for him, among them the famous letter to the king of the Khazars.

The Mahberet is his dictionary. Before him dictionaries of Hebrew were written in Arabic; this one is written in Hebrew, and it is the first to cover the whole vocabulary of the Bible. His account of the root is not yet the one that would prevail: he counted roots of one, two and three letters, and later scholarship did not accept it. But the task had been set, and the book became the one everyone pushed off from.

What followed went badly. Dunash ben Labrat came from the Maghreb and wrote a critique of his dictionary—sharp, and dedicated to Hasdai. The patron turned at once. Menahem was thrown out of his house—and, by his own account, on the Sabbath—beaten and imprisoned. He wrote Hasdai a letter which survives: there is no pleading in it, but an argument that the patron had acted contrary to the law.

His students defended him. One of them, Judah Hayyuj, proved a generation later what the teacher had not proved—and on that all later grammar stands. So Menahem lost the argument, and his cause won.