She planned a trilogy set during the 18th century, of which only Madame Dorothea was written, but she did finish a tetralogy that began with The Axe and centered on the murderous Master of Hestviken.  
In this author's third novel, a young artist leaves her fianc? for his father Gert before committing suicide in Rome.  This author's second novel, set in the 11th century,  centers on the rape of a young woman named Vigdis.  While infidelity was the subject of early novels like  Jenny and Frau Marta Oulie, this author's conversion to Roman Catholicism had an impact on later works like The Faithful Wife and The Wild Orchid.  She planned a trilogy set during the 18th century, of which only Madame Dorothea was written, but she did finish a tetralogy that began with The Axe and centered on the murderous Master of Hestviken.  FTP, name this author of The Bridal Wreath, which was the first volume of a trilogy about Kristin Lavransdotter.
In this author's third novel, a young artist leaves her fianc? for his father Gert before committing suicide in Rome.  
Sigrid Undset