Joasia, three years ago, your remark about Liza in The Sound of Music must have referred to Liesl.
Somewhere, I have the autobiography of Maria Von Trapp "The Story of the Von Trapp Family Singers" [ 1954 ]. I never got around to reading it, but did see an article which broke the bad news that Liesl was a creation of Hollywood.
Remember the famous "I am 16, going on 17, innocent as a rose" song ? Liesl sang that in a scene in a gazebo with Rolfe, the telegram delivery boy, I seem to recall. Instead the oldest Von Trapp child was a boy, and not nearly as romantic a figure as the fictional Liesl. Incidentally, the actress who played her had no more major roles after that. After writing 2 books "Forever Liesl" and "Letters to Liesl", Charmain Carr reposed September, 2016 from a rare type of dementia.
Quite a telling of an alteration to the true life story by the American arts scene was the elimination of a highly important figure in the Von Trapp family lives : a Catholic priest. I see that as underhanded. This was only 1965 ! What about today ?
But it was another important figure in their life, the priest, Father Franz Wasner, who was instrumental in their musical success, touring with them in Europe and America. He was left out of both the film and the Broadway musical.
http://www.bbc.com/news/magazine-31658799
Then, too, the only reason this film was even made always seemed to me to have been because of its anti-Nazi propaganda value. How many young American and European girls saw themselves as Liesl, after all ? People of all ages uncritically absorbed the message of the movie because of its plot line of an endearing family's vicissitudes under threat from the Nazis.
But where were the GP-Family Audience films made to educate a largely ignorant American populace against the horrors of the Soviet Union under Lenin or Stalin ???
How many interesting families must escaped Russia and Eastern Europe in similarly or even more dramatic circumstances ? Strange that only this one was selected for Broadway and Hollywood.