Here's one about an early instance of what would now be called trolling:

In the late 1950s a cubist painter from the early 20th century, friend of people like Pablo Picasso and Piet Mondrian, was suddenly rediscovered when a more or less well-known novelist published that painter's biography. The paintings were shown in exhibitions, critics and gallerists remembered him etc.
After sitting back and watching the confusion for a while, the author of the biography admitted that he had made everything up and even painted the pictures himself.
Name the (real) author or the (fictional) painter.