1886:

The Cambridge School for Girls is established by Arthur and Stella Scott Gilman at 20 Mason Street in Cambridge, Massachusetts. Also known as The Gilman School, the school's mission is to prepare young girls for Radcliffe College. Boys are accepted through third grade. Six years later in 1893, the school moves to 79 Brattle Street, Cambridge (on the Radcliffe campus), and, in 1897, moves once again to 36 Concord Ave, Cambridge.

1891:

"Truthe and Gentil Dedes" is adopted from Chaucer as the motto for the school.

1896:

Helen Keller is accepted as a student and studies at the school for one year.

1918:

The Cambridge School for Girls merges with the Haskell School (formerly on Marlborough St, Boston) and becomes the Cambridge-Haskell School. Mary E. Haskell is head of school. For several years, Haskell sustains a close relationship with renowned Lebanese poet Kahlil Gibran. Gibran designs a school ring (a flower growing in an open hand) for the Cambridge-Haskell students.