I found an example
It is like this:
* * *
When
Fyodor Dostoevsky was twenty-eight, he was arrested by the
Czar's secret police and sentenced to death, along with other
members of a group that supported revolutionary political and social
ideas. (His particular crime was publishing illegal articles
advocating changes in Russian society.) When the prisoners
were
bound and waiting to be shot, and as the Czar's firing squad readied
for the execution, a royal messenger dramatically announced a
reprieve. The men's lives were spared.
The spectacular salvation had been prearranged. The Czar had
merely wanted to frighten the men and demonstrate his power.
Dostoevsky got the message. More important, his escape from death-
followed by four years of imprisonment in Siberia- had an enormous
impact on his life and work.
* * *
In Crime and Punishment roman, , Raskolnikov,
the main character, suddenly feels "a boundlessly full and powerful
life welling up in him." He compares the emotion to the reaction of "a
man condemned to death and unexpectedly reprieved."
* * *
If people know Dostoyevski's real happened event, they get Raskolnikov's feeling completely, see the paralellism, and with them, in my opinion, people understand the roman entirely.