The charter members of Alpha Chapter pose together with a trident. Pictured are, back row, left to right: Marion Norris, Margaret Emerson, Emily Allen, Blanche Seaver, Della Badger, Bertha Gardner, Hannah Center, Maude Muzzy, and Grace Gallison; middle row, left to right: Isabel Breed, Eleanor Pond, Sarah Shaw, Hattie MacNeil, and Lotta Stevens; front row, left to right: Charlotte Joslin, Bertha Brackett, Alice Elizabeth Rich, Florence Stewart, Emily Clough, Mattie Carter, and Myrtle Burdett.
Once all four founders had joined Tri Delta, they began working to grow the society. Before long, three girls from the junior class, including Emily Allen, the first editor of The Trident, were ready to become members, along with five sophomores and six first years. The young women ordered 18 pins from a local jeweler and planned an initiation for the new year.
On January 15, 1889, Tri Delta's first initiation was held, with Florence Stewart, Isabelle Breed, Lotta Stevens, Hattie MacNeil, and Emily Allen becoming full-fledged members of Tri Delta. The ceremony was held in a classroom of the Boston University building at 12 Somerset Street. The founders and new members immediately returned to their rooms to prepare for a more formal initiation ceremony to be held that evening for the remaining 11 women, bringing Tri Delta to a membership of 18. Emily Allen later wrote, "No happier girls could be found in Boston when we the eighteen initiates formed Alpha Chapter of Delta Delta Delta and the fraternity's life as an organization was begun."
