A Dutch school director preparing an exhibition on Anne Frank has found a Christmas postcard signed by the Jewish teenage diarist, a museum said Wednesday.

The card was sent in 1937 and addressed to Samme Ledermann, one of Frank's best friends, and postmarked from Aachen, a town just across the Dutch border in Germany, said Maatje Mostard, of the Anne Frank Museum.

Anne, her parents and sister and four other Jews hiding in the apartment were arrested in August 1944 and deported to Auschwitz. The sisters were later sent to the Bergen-Belsen concentration camp where Anne died of typhus in March 1945, two weeks before the camp was liberated. She was 15.