Just found out the above link leads not to the article I quoted! Therefore here comes the quote:
"The recently published book, "Kate In Fact and Fiction," is the intriguing story of the survival of Sara Catherine King, who at age 13 alienated her family by running away from her Blue Springs home during the Civil War and marrying the notorious guerrilla leader.
Three and a half years later, their marriage ended with Quantrill's 1865 murder in Kentucky. The 17-year-old widow found herself alone in St. Louis, living a life in refuge as Kate Clarke.
[...] She was by herself in St. Louis and didn't know what to do or how to survive. Back then, there wasn't a lot (for a woman to do). You could be a seamstress, you could be a cook or you could do things that weren't so honorable" – like prostitution. Kate chose the latter; soon she became madam Kate Clarke at one of the finest bordellos in St. Louis.