A dramatized biography is one way that dramatists and authors can "fill in" the blanks in an historical play or novel they are writing.
The subject of the play or novel may have huge holes in their biography. That is, the subject might have a well-known childhood, but up until middle age, that entire part of their life is unknown. There may be no writings, no diaries, no journals, no way of knowing what they did or how they grew up, or more importantly, how to know what events influenced and affected their lives.
If little is known about the subject of the play or novel, the writer may have to "craft" events out of what he or she thinks may have happened.
The writer may have some clues. Perhaps a few sentences are mentioned in the diary of a sibling, or maybe there is a newspaper article that describes an event, even a tragedy, that befell the family of the subject of the play or book.
There is no way that the writer can know exactly what kind of an impact a tragedy, for example, had upon the subject of his writing. The writer has to do more research, discover what he or she can, and see if that fits into what the writer already knows.
However, suppose there is no more information to be had? Suppose all the writer knows is what's on a yellowed piece of newsprint? The writer has to make a best guess, or leave an entire decade or more out of the life of the subject.
It might not be enough to just guess. For a biography, or a play, or a novel, it might just be too dry and uninteresting for an audience.
This is where the creativity of the writer comes in. Suppose the writer looks again at the tragedy in the newsprint that involved the subject's family, and then looks into the later known life of the man for which the writer is creating a biography.
Let's say that the subject's sister died after an illness, and from the biography that is known, the subject was extremely upset. The subject didn't easily get over his sister's death, and in fact, it seemed to cast a pall over his entire life and becomes a major theme in his biography.
The writer could make an educated guess that the tragedy of the subject's earlier years may have had a profound effect on the entire life of the subject. The later, adulthood death of his sister could, in fact, have been a horrible reminder of the tragedy of his earlier years.
So now the writer has some solid evidence for a theory: that the earlier tragedy described in the newspaper article is connected to the subject, that as an adult the death of the subject's sister had a profound impact upon him, much more so than one might expect in an adult male of an earlier era where the premature death of people was a much more common event than now.
The writer can make a fairly educated guess that the earlier tragedy had a big effect on the subject into his adult life. But the writer has no direct evidence for this - no quotes, diaries or evidence that any of this happened. What the writer has is a really good theory.
So what does the writer do? The writer dramatizes what he or she knows. The facts as they are, and any theory, are the bones upon which the writer drapes the filler of what may have happened.
This especially important in a work such as a play or a movie. A mere guess, or hedging a theory in too many dry-sounding words, would just put an audience to sleep.
The writer has to use creativity to make a theory come to life, but conversely, the writer doesn't want to make up the missing events of the subject's life. Not unless he or she wants the book or play to be scoffed at as mere fiction. One thing it should be is grounded in the facts, whatever they may be.