Poland ? A museum has acquired a collection of rare World War II-era postcards, stamps and letters from Polish insurgents who fought their Nazi occupiers during the Warsaw Uprising.

Included in the 123 items are postage stamps printed by insurgents with seals made from potatoes, and letters and postcards that describe the fighters’ plight. Some of the letters had never been opened.

Jan Oldakowski, director of the Warsaw Uprising Museum, said Saturday that the museum bought the collection at auction in Duesseldorf, Germany, for the asking price of $280,000. The auction house could not immediately be reached for confirmation.

Germany offered to cover the cost of the collection, but Poland decided to purchase the items on its own, Culture Minister Bogdan Zdrojewski told TVN24 television.

Oldakowski said the museum was trying to track down people who wrote or received the mail. He said two people have already come forward.