Not strictly related but I recall once hearing that Bach may have never heard his Brandenburg concertos performed.

Looking at Wikipedia now I see:

"Because King Frederick William I of Prussia was not a significant patron of the arts, Christian Ludwig seems to have lacked the musicians in his Berlin ensemble to perform the concertos. The full score was left unused in the Margrave's library until his death in 1734 [and] was only rediscovered in the archives of Brandenburg by Siegfried Wilhelm Dehn in 1849"

I have just switched them on and feel very grateful that I can.