Sixty years ago Monday, Anne Frank's father published the first version of his daughter's diary under the title "Secret Annex."

The personal account of life in hiding during the Nazi occupation of the Netherlands was later translated into nearly 100 languages -- the English version first appeared in 1952 -- and has sold tens of millions of copies worldwide.

Unpublished family documents

In honor of the anniversary, Anne Frank's 82-year-old cousin Buddy Elias in Basel, Switzerland, has permanently loaned 25,000 documents, letters and photographs to the Anne Frank Foundation in Amsterdam.

The archive's contents, which Elias had kept in his attic for decades, range from 19th century family photos to post-war letters after the publication of the diary, many of which have never been published before. For the first time, all known historical material about the Frank family will be under one roof.

In addition, two symposiums were organized for scholars to discuss both the literary and historical significance of the young girl's diary as well as problems presented by translating it.

"Anne Frank writes about scenes and problems all teenagers deal with, such as relationships with parents and siblings, but also about her will to make the world a better place," Patricia Bosboom, spokeswoman for the Anne Frank Foundation in Amsterdam, told the German news agency dpa.

Literary importance of diary

"Previously, the diary was studied primarily as a historical document," continued Bosboom. "Today, its literary qualities are acknowledged too."

Anne Frank, born in 1929 in Germany, fled with her Jewish family to the Netherlands when Hitler came to power in 1933. When the Nazis invaded and took control of their western neighbor, the Frank family was forced to go into hiding.

For two years, Anne kept an account of her life in hiding, which would later come to be considered a paramount document on the era.

The Frank family was betrayed, arrested and deported to various concentration camps in August 1944. Anne died of typhus in the Nazi camp in Bergen-Belsen in March 1945.

Anne's father, Otto Frank, was the only survivor. He published his daughter's diary, which had been saved by members of the resistance, in 1947.