Theodore Parker’s grandfather commanded the Lexington Minutemen on April 19, 1775. Theodore himself battled against holy ignorance and unholy slavery. His 1841 sermon on “The Transient and Permanent in Christianity” resulted in his isolation from most Unitarian colleagues. Some Unitarians of Boston, however, soon made him the most powerful preacher in the city when they organized the Twenty-eighth Congregational Society of Boston. His radical reforms and applied Transcendentalism were undergirded by his triple affirmation of "God, Duty, and Immortality." Two biographies of his life are Theodore Parker: Yankee Crusader by Henry Steele Commager and American Heretic: Theodore Parker by Dean Grodzins.