Tim, J. S. Bach is not the only genius whose work has been attributed to his wife on flimsy grounds. Back in the 1990s, feminists tried to make a case that Albert Einstein’s first wife had “done his math” for him. It was controversial back then, and the weight of scholarly opinion was strongly against it, but a generation later Mrs. Einstein continues to be invoked as a tragically mistreated mathematical whiz, making necessary new rounds of debunking.
A similar but less prominent case involves Charles Hall, who in the 1880s discovered the method that is still in use to isolate metallic aluminum from bauxite (it isn’t easy). He was not married, but revisionists have suggested that his sister, Julia, with whom he lived, participated in his research and should be credited as co-discoverer. As with Bach’s and Einstein’s wives, Julia does seem to have had some involvement with Charles’s work, but her role has been greatly inflated, to the point where one popular source calls them “a brother and sister team.”
And this is a bit off topic, but if the Bach revisionists succeed in getting Anna Magdalena credited as co-composer, it won’t be the first time that co-authorship of a famous piece of music was retroactively attributed to a clerical assistant. In 2002 an Italian court ruled that Alfredo Mazzucchi was a co-composer of “O Sole Mio” (1898). Mazzucchi, who was 19 at the time, is generally described as a transcriber for the songwriters Giovanni Capurro and Eduardo Di Capua, but the court decided that he had contributed to writing the melody as well.
Why did a court even get involved? Copyright on musical works expires 70 years after the death of the last co-creator. Capurro and Di Capua died in 1917 and 1929, respectively, but Mazzucchi stayed alive until 1972, when he died at age 93 — which means that a song that came out in 1898 will remain in copyright until 2042.