Born: November 28, 1822, Boston, Massachusetts.
Died: November 27, 1895, Boston, Massachusetts.
Buried: Mount Auburn Cemetery, Cambridge, Massachusetts.
Octavius was the son of Nathaniel Langdon Frothingham and Ann Gorham Brooks, and husband of Caroline Elizabeth Curtis.
He graduated from Harvard University (1843) and Harvard Divinity School (1846).
He served pastorates North Church, Salem, Massachusetts (1847–55); the Independent Liberal Church, Jersey City, New Jersey (1855–59); and the Third Congregational Unitarian Society, New York City (1859–79).
He was known as a leader of the Free Religious
movement.