Hambourg, Isabelle McClung (1877-1938). Cather’s longtime friend. Cather met Isabelle McClung, the daughter of a socially prominent, Pittsburgh (PA) family, in 1899 in the dressing room of actress Lizzie Hudson Collier. McClung seems to have been the first woman to reciprocate Cather’s romantic affections. In 1901, McClung invited Cather to live in her family’s large home in the Squirrel Hill neighborhood of Pittsburgh. She and Cather traveled together to Europe in 1902, and McClung accompanied Cather on a visit home to Nebraska in 1905. After Cather moved to New York City in 1906, she frequently visited McClung in Pittsburgh, finding the familiar house a congenial place to write, and McClung visited New York City, staying with Cather and Edith Lewis. Cather and McClung also rented a vacation cabin in Cherry Valley, NY, in 1911, and traveled together to Virginia in 1913. In late 1915, shortly after the death of her father, Judge Samuel McClung, Isabelle announced her intention to marry violinist Jan Hambourg. Cather reacted negatively to the marriage (which took place in 1916) but eventually reconciled herself to it, enjoying long visits with the Hambourgs in Toronto, Ontario, in 1921 and France in 1923 and 1935. Cather and Edith Lewis also spent time with the Hambourgs in Paris is 1930 and 1935. The latter trip occurred after Isabelle sought treatment in the U.S. for the kidney disease that killed her several years later in Italy. Her death came only four months after Cather’s brother Douglass died, leaving her feeling bereft. “No other living person cared as much about my work, through thirty-eight years,” she wrote her brother Roscoe (#2137). After Isabelle’s death, Jan sent to Cather the six hundred letters from Cather to Isabelle in his possession, and Cather destroyed them, although a few letters from Isabelle and Cather postcards to Isabelle are extant.

Flexner, Simon (1863-1946). American medical researcher and administrator. Born in Louisville, KY, fourth son of Jewish immigrants Moritz and Esther Flexner, Simon Flexner worked in his brother’s drugstore and attended pharmacy college and then medical school in Louisville. After postgraduate work at Johns Hopkins, he taught at the University of Pennsylvania until 1903, when he went to the Rockefeller Institute for Medical Research. He served there as director until his retirement in 1935. In 1903 he married Helen Whitall Thomas, who taught English at Bryn Mawr. They had two sons, William Flexner, a physicist, and James Thomas Flexner, a writer and biographer.

Flexner, Helen Whitall Thomas (1871-1956). American writer and educator. Born in Baltimore, MD, into a prominent Quaker family, Helen Thomas attended Bryn Mawr College, where her elder sister, M. Carey Thomas, was then dean and later president. She graduated in 1893 and studied abroad for a year. Returning, she became an instructor of English composition at Bryn Mawr. In 1898 she met medical researcher Simon Flexner; they married in 1903, and had two sons, William Flexner, a physicist, and James Thomas Flexner, a writer and biographer. Flexner published her own autobiography, A Quaker Childhood, in 1940. Cather’s friend, Elizabeth Sergeant, had studied under Flexner, and was the Flexner's neighbor when O Pioneers! was published; Sergeant showed the book to Flexner, who was interested in it, although she criticized one of Cather’s word choices. It is unclear whether Cather met the Flexners.