Jalna, by Mazo de la Roche, is, according to Wikipedia, "the first of a 16-novel family saga about the Whiteoak family. John Cromwell directed a 1935 film adaptation, Jalna. In 1972, it was filmed for television as The Whiteoaks of Jalna." [link added]
Jalna Revisited, from exhibitions of the Museums of Mississauga, included the following information:
"The first three years of ‘Masie’ Roche’s life were spent in Newmarket at her grandparent’s and were followed by as many as seventeen moves."
"Another contributing factor in forming Mazo’s early life was the constant poor health of her mother. Mazo’s autobiography is filled with many examples of sacrifice in order to please her mother...".
"Caroline Clement was Mazo’s cousin but also her best friend and life-long companion [link added]. In Mazo’s autobiography, Ringing the Changes, she starts the book saying “Although I did not realize it at the time, or for many years afterward, that January day in my maternal grandfather’s house, was the most important day of my life”. It was the day Caroline came to live with her family."
A review of by Dorothy Livesay of Ronald Hambleton's Mazo de la Roche of Jalna, here.
Per the Mazo de la Roche Society:
"The creation of the Jalna books is the most single feat of literary invention in the brief history of Canada's literature."