William Perrin Nicolson, Sr., (b. ca. 1858) was born in Virginia to Betty B. and George L. Nicolson, a physician. In 1891, after medical school, William, Sr., married Caroline Clayton Crane (b. 1869), the daughter of Sarah C. Clayton and Benjamin Elliott Crane, a merchant, of Athens and then Atlanta, Georgia. Benjamin's father, Ross Crane, had come to Georgia from New Jersey early in the 19th century. Sarah Clayton was the daughter of Caroline M. Semmes and William Wirt Clayton. In the 1890s, the Nicolsons built a house on Piedmont Avenue in what became Midtown Atlanta. They had three children, the eldest, William P., Jr., (1893 - 1969) also became a physician. He married Elizabeth Tuller of Atlanta, who had traveled to Europe at the end of the war as part of the Women's Overseas Service League, Atlanta unit.