From the late 1920s into the 1930s, at the height of the Great Depression, people of Scandinavian descent all across the United States thought they had found their way out of financial ruin. A supposed fortune had been sitting in an Amsterdam bank for over a hundred years, waiting for the great-great-great-great-great grandchildren of the estate to step forward and claim their fortune.
The Nigerian Prince & other scams have a long history. This particular scam dates to the 1920s and lasted at least a decade.