The source novel was virtually banned in West Germany when it was first published in the late 1950s. When it was republished in 2003, it became a huge bestseller and nationwide sensation in a reunified Germany.
Anonyma was later revealed to be journalist Marta Hillers.
The movie's source novel is the diary of an unnamed woman, called Anonyma, from April 29, 1945 to June 22, 1945.
As a protective measure the author requested her anonymity as author of her book: Eine Frau in Berlin (A Woman In Berlin).
In the four months that the Soviet army occupied Berlin, the soldiers raped an estimated 95,000 to 130,000 females. A Soviet war correspondent reported that soldiers were raping every German female "between 8 and 80."