Nadezhda von Meck
Karl died suddenly in 1873.  Nadezhda took over his business matters.  She sold one railway and controlled the other one with the help of her brother.  She kept away from other people, living a solitary life with her children.  She was very strict indeed with them, telling them exactly what to do all the time.  She did not like the idea of marriage, but realized her children would need to marry.  She tried to get them to marry quickly, probably for financial reasons.