Sentence:  McPherson's healing ministry, in fact. was at the core of her success, since so many of the <WSD>Folks</WSD> had come to Southern California in late middle or old age in the hope of regaining lost health. 
Meaning of the word marked with <WSD> tags:  Late 19th and early 20th century migrants to California from Iowa and other parts of the Midwestern United States.