Many of the cantatas written by J.S. Bach during his tenure at St. Thomas' church in Leipzig were lost after his death. I was in high school when I first read the horrifying stories about this great music being used as scrap paper, to wrap fish and cheese, or wrapped around trees as protection from insects.
Many of these stories are, in fact, embellished or apocryphal. Most of the Leipzig cantatas were distributed between his two oldest sons upon his death, and about a hundred of these appear to have been permanently "misplaced". (If any of these survived into the twentieth century without being found, they were undoubtably destroyed during World War II.) Other works, which had been presented to various VIP's as gifts, were indeed eventually given away as scrap paper, along with all the other musical gifts from other composers. And, of course, the instrumental parts would have been considered expendable, since they could always be re-created from the autograph score (although in many cases, the score has had to be recreated from the parts). So, even though a hundred or so cantatas were indeed lost, there is no reason to believe they were treated with the callous disregard described by the popular anecdotes.
Nevertheless, those stories created in me a powerful desire to restore what had been lost. Ever since I first learned of these lost works, it has been my dream to take the few of these cantatas where the text was preserved and attempt to reconstruct the cantata as Bach would have written it. In most cases I have avoided re-using existing works of Bach (unless it is known that Bach used "parodies" in the missing works), but composed new music in the style of Bach. Rather than borrowing fully-formed musical ideas from the great composer, I borrowed the compositional rhetoric he employed, as was so thoroughly documented by musicologists such as Albert Schweitzer.
Here are the fruits of my labor so far.
These organ works served as a sort of "warm-up" in preparation for the more ambitious choral works.
Many thanks to Z. Phillip Ambrose for the texts of the lost cantatas.