He was born in
Boston, Massachusetts, the son of
Nathaniel Langdon Frothingham (1793–1870), a prominent
Unitarian preacher, and through his mother's family he was related to
Phillips Brooks. He graduated from
Harvard College in 1843 and from the Divinity School in 1846. On March 23, 1847, he married Caroline Martha Curtis (February 5, 1825 - June 8, 1900).
Pastorates He was pastor of the North Unitarian church of
Salem, Massachusetts, from 1847 to 1855. He broke with this congregation over the issue of slavery. From 1855 to 1860, he was pastor of a new Unitarian society in
Jersey City. There he gave up the
Lord's Supper, thinking that it ministered to self-satisfaction. It was as a radical Unitarian that he became pastor of another young church in
New York City in 1860. The name of the church was initially the Third Unitarian Congregational Church. From the beginning, Frothingham belonged to the most radical wing of the Unitarians. Indeed, in 1864 he was recognized as leader of the radicals after his reply to
Frederic Henry Hedge's address to the graduating students of the Divinity School on "Anti-
Supernaturalism in the Pulpit." In 1865, when he had practically given up
transcendentalism, his church building was sold and his congregation began to worship in Lyric Hall under the name of the Independent Liberal Church, their connection with the Unitarian denomination being thereby sundered. He was cremated, and his ashes were buried at
Mount Auburn Cemetery. ==Published works==