“How do we collect it?” asked Bill. “If the Nazis grabbed them, aren’t they real for sure?”

“Not necessarily,” Dad continued. “The Nazis were fooled sometimes by people who sold them fakes. There was one painting that Hitler’s sidekick, Göring, bought that was supposed to be a 17th century painting by Vermeer, a Dutch painter. Because Vermeer’s work is so valuable, it’s usually impossible to buy one for any amount of money.

“Vermeer is regarded as a national hero by the Dutch. The matter was investigated and the painting traced to Han Van Meegeren, a modern Dutch painter who had only a fair talent. When Van Meegeren realized he might be charged with treason by the Dutch for selling a Vermeer to the Nazis, he confessed that he had painted it himself. He also confessed that he had painted other forgeries that fooled some of the experts and were sold for a lot of money.

“Many people, however, thought Van Meegeren was only lying to save himself from the charge of treason, and the whole thing had to be decided by a committee of scientific art experts appointed by a court of law. Using the methods that were then available, the experts showed that Van Meegeren had done a remarkable job of forgery and they were convinced that he had been telling the truth about painting those pictures.

“At the time, the important ways the experts used to examine a painting included studying the work with X rays, which could show another painting underneath, analyzing the pigments (or coloring materials) used in the paint, and examining the painting for certain signs of old age.

Han Van Meegeren listens to the evidence at his trial in Amsterdam. In the background is “The Blessing of Jacob”, which was sold in 1942 as the work of Vermeer.

An authentic Pieter de Hooch work, “The Card Players”, painted in the 17th century.