The history of sororities

[AGDAlum]

To add to this is the P.E.O. Sisterhood, founded in 1869 at Iowa Wesleyan College.

Of its seven founders, some had been asked to join the I.C. Sorosis at IWC but some had not. They wanted to stay together so they founded "a society of [their] own." P.E.O. chose to retain English letters and to become a community, rather than a collegiate, organization [in the 1880's, IIRC]. Chapter Original A at IWC is Alpha Xi Delta; the I.C. chapter (Pi Phi for lo these many years--Iowa Alpha?) is still there.

P.E.O. is larger than any one NPC group in terms of initiated members and chapters. Probably also larger in terms of assets in the charitable foundation which funds P.E.O.'s projects. Many, many NPC members are also P.E.O.s. (www.peointernational.org will tell you more.)

AGDAlum (who is also a P.E.O.)

Originally posted by breathesgelatin
Here is a list. If there are any corrections let me know.

In sum:
Alpha Delta Pi Sorority, 1851 (Adelphean Society became a Sorority in 1904)
Phi Mu Fraternity, 1852 (Philomathean Society became a Fraternity in 1904)
Pi Beta Phi Fraternity, 1867 (I. C. Sorosis Fraternity adopted motto PBF in 1882)
Kappa Alpha Theta Fraternity, 1870 (January 27)
Kappa Kappa Gamma Fraternity, 1870 (October 13)
Alpha Phi Fraternity, 1872
Delta Gamma Fraternity, 1873
Sigma Kappa Sorority, 1874 (November 9) (Founded as a Fraternity, became a Sorority in 1904)
Gamma Phi Beta Sorority, 1874 (November 11)
Alpha Chi Omega Fraternity, 1885
Delta Delta Delta Fraternity, 1888
Alpha Xi Delta Fraternity, 1893 (founded as a Sorority, became a Fraternity in 1913)
Chi Omega Fraternity, 1895
Alpha Omicron Pi Fraternity, 1897 (January 2)
Kappa Delta Sorority, 1897 (October 23) (don't know if it changed)
Sigma Sigma Sigma Sorority, 1898 (April 20) (don't know if it changed)
Zeta Tau Alpha Fraternity, 1898 (October 15)
Alpha Sigma Tau Sorority, 1899 (founded as a Fraternity, became a Sorority in 1935)
Alpha Sigma Alpha Sorority, 1901
Delta Zeta Sorority, 1902
Alpha Gamma Delta Fraternity, 1904
Alpha Epsilon Phi Sorority, 1909
Theta Phi Alpha Fraternity, 1912
Phi Sigma Sigma Fraternity, 1913
Delta Phi Epsilon Sorority, 1917 (March 17)
Sigma Delta Tau Sorority, 1917 (March 25)