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FUERTH, Germany (AP) — Historical records from the prison that held Adolf Hitler in 1924 documenting the future dictator's time behind bars sold to an anonymous bidder for euro27,000 ($33,400) Friday at an auction in Germany.

The approximately 500 documents from the Landsberg prison were recently found by a Nuremberg man among the possessions of his late father, who had purchased them at a flea market in the 1970s, according to Werner Behringer, whose auction house put them up for sale.

The Bavarian State Archives in Munich examined photographs of the documents and said they appeared genuine, though the experts said the authenticity could not be guaranteed without the originals in hand.

Though only one document is signed by Hitler himself, and much of the information about his time in prison is otherwise available, they do provide an intriguing window into his early days as Nazi leader.

Among other things, they show he enjoyed a comfortable time at the prison, being allowed hundreds of visitors — sometimes unsupervised — including some 30 to 40 people to celebrate his 35th birthday.

Hitler was imprisoned in Landsberg after the Nazi's abortive bid to seize power in 1923 in the notorious "beer hall putsch" coup attempt in Munich. It wasn't until a decade later, in 1933, that the Nazis would eventually come to power through parliamentary elections.

Despite being sentenced to five years in prison, Hitler was granted early release and ended up only serving about nine months of his sentence.

His right-wing politics and German nationalism won him some high-placed friends among the German establishment, including World War I hero Gen. Erich Ludendorff. Ludendorff came to visit Hitler several times during his imprisonment, and the Prussian general was allowed to see the former Austrian corporal unsupervised for as long as he wanted, the documents show.

Prison director Otto Leybold gushed about Hitler in a memo about the inmates on Sept. 18, 1924, saying he was always "sensible, modest, humble and polite to everyone — especially to the officers of the facility."