At Dams (Italian auction house), they sell next week a 17th century Saint Sebastian. They don't seem to realise that it is a copy of a work by Guercino which was only rediscovered (or correctly attributed) in late 2014. The estimate of 1,800 Euro seems rather steep for a fairly mediocre copy though, but it makes for an interesting story. I don't know whether other old copies of the same work are known.
