Mrs. Patrick Campbell was a hugely famous actress in the early 20th century, though she hasn’t really retained her iconic status. She quickly had a reputation as a stage diva with a sharp tongue, and originated one of the most beloved characters of the stage and screen.
Research:

Campbell, Mrs. Patrick. “My Life and Some Letters.” New York. Dodd, Mead. 1922. Accessed online: https://archive.org/details/mylifesomeletter00camp
Sudermann, Hermann. “Magda.” Lamson, Wolffe and Company. New York. 1895. Accessed online: https://www.gutenberg.org/cache/epub/34184/pg34184-images.html
Woods, Leigh. “’The Golden Calf’: Noted English Actresses in American Vaudeville, 1904-1916.” Journal of American Culture. 1992. https://www.academia.edu/47469417/The_Golden_Calf_Noted_English_Actresses_in_American_Vaudeville_1904_1916
Aston, Elaine. “Campbell [née Tanner], Beatrice Stella [performing name Mrs Patrick Campbell].” Oxford Dictionary of National Biography. Jan. 3, 2008. https://doi.org/10.1093/ref:odnb/32261
Whitaker, Alma. “Personal Reminiscences of Mrs. Patrick Campbell.” Los Angeles Sunday Times. Nov. 3, 1912. https://www.newspapers.com/image/380204798/?terms=Mrs.%20Patrick%20Campbell&match=1
Peters, Margot. “Mrs. Pat: The Life of Mrs. Patrick Campbell.” Bodley Head. 1984.
“Famous Actress at Death’s Door.” Salt Lake Tribune. Sept. 19, 1912. https://www.newspapers.com/image/76001747/?terms=Mrs.%20Patrick%20Campbell&match=1
“Mrs. Patrick Campbell Ill.” The Brooklyn Daily Eagle. Sept. 20, 1912. https://www.newspapers.com/image/54225938/?terms=Mrs.%20Patrick%20Campbell&match=1
Britannica, The Editors of Encyclopaedia. "problem play". Encyclopedia Britannica, 20 Jul. 1998, https://www.britannica.com/art/problem-play
Britannica, The Editors of Encyclopaedia. "Mrs. Patrick Campbell". Encyclopedia Britannica, 5 Apr. 2023, https://www.britannica.com/biography/Mrs-Patrick-Campbell
“Mrs. Campbell, 75, Famous Actress.” New York Times. April 11, 1940. https://timesmachine.nytimes.com/timesmachine/1940/04/11/92937919.pdf?pdf_redirect=true&ip=0
Shaw, George Bernard. “Pygmalion.” 1912. Digitized March 1, 2003. https://www.gutenberg.org/files/3825/3825-h/3825-h.htm
Atkinson, J. Brooks. “Mrs. Campbell Returns.” New York Times. Feb. 8, 1927. https://timesmachine.nytimes.com/timesmachine/1927/02/08/110039988.pdf?pdf_redirect=true&ip=0
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