Historically Speaking— The Witch of Agnesi—Exorcised

Abstract

In the summer of 1965, at an informal luncheon attended by a prominent algebraist, the name of Maria Gaetana Agnesi and the curve known as the Witch of Agnesi were mentioned. The algebraist asked: “Wasn't this curve called the ‘Witch’ because Agnesi knew how to read and write when this was unusual for women? Wasn't she burned at the stake in the thirteenth century?” Now, Maria Gaetana Agnesi (1718-1799) died quietly in a home for the aged where she had been director of women for many years. Her tombstone was inscribed “noted for piety, learning and good works.” These facts are known to contemporary historians of mathematics. The gross errors of our algebraist are not likely to be repeated, but the legends concerning Agnesi and the Witch seem to die slowly. Perhaps this justifies the appearance of yet another note on the subject.