At his death in 1794, Czech composer František Xaver Pokorný had written more than 160 symphonies, concertos, serenades, and divertimentos. But more than half of them were then reattributed to other composers. The culprit was apparently Theodor von Schacht, a competing Regensburg composer who may have been jealous of Pokorný’s large output.
After Pokorný’s death it appears that Schacht went through more than half his compositions, systematically removed Pokorný’s name, and inserted the name of another composer who he thought might not find out. He assigned most of the pieces to composers whose names began with A or B.
It wasn’t until the early 1960s that musicologists Jan la Rue and J. Murray Barbour uncovered this odd crime and Pokorný was given proper credit.