Phi Sigma Sigma was the first Non-sectarian sorority.
From
www.phisigmasigma.org
"The early 1900's were turbulent times. Racial vindictiveness emerged as a result of earlier waves of emigration, and divisions developed along religious, ethnic, and economic lines. The city of New York was seen as a cauldron for social change.
In 1913, our Founders Lillian Gordon, Ethel Gordon, Josephine Ellison, Shirley Cohen, Fay Chertkoff, Claire Wunder, Estelle Melnick, Rose Sher, Jeanette Lipka, and Gwen Rae Zaliels approached the Dean of Women at Hunter College in New York City with a vision. They wanted to start a sorority that would promote open membership to all women of character regardless of background; a sorority committed to sisterhood, excellence in scholarship, and selfless giving.
On November 26, 1913, Phi Sigma Sigma was born, unobtrusively, without the thought of expansion. It was the first nonsectarian sorority; the only one that was open to diverse membership from inception and the only one with a ritual that was not based in scripture. "