A new study provides "conclusive evidence" that composer Ludwig van Beethoven died of lead poisoning. However, it isn't clear where the lead came from:

Still a mystery, however, is the source of Beethoven's lead exposure, which evidence now suggests occurred over many years. Among the possibilities are his liberal indulgence in wine consumed from lead cups or perhaps a lifetime of medical treatments, which in the 19th century were often laced with heavy metals. (Washington Post)