I love these kinds of stories. A New York family discovered that a painting they had behind their couch for 30 years is probably a Michelangelo painted almost 500 years ago and maybe worth an estimated $300M. The painting used to be hanging on the wall of their house until a tennis ball knocked it off. Everyone in the family had always heard the legend it was a Michelangelo but nobody really did any investigating until after one of the family retired and was given the task of checking.
He checked and checked and convinced some experts to take a look at it and examined how it came to be in this upstate New York house. The painting in the home is not a new discovery. There are records of its existence and is mentioned in Vatican letters dating from that time period. Here is how it got to be in the house.
The painting was passed to two Catholic cardinals, eventually ending up in the hands of a German baroness named Villani. The work ended up in the New York family after Villani willed it to her lady-in-waiting Gertrude Young. Young was the sister-in-law of the family's great-grandfather and she sent the work to America in 1883.