September 15, 1863, Auburndale, Massachusetts.
December 18, 1919, Cedarhurst, New York. He caught pneumonia while preparing for a trip to the West Indies for health reasons.
St. Mary’s Cemetery, Newton Lower Falls, Massachusetts.
Horatio was the son of Charles Edward Parker and Isabella Graham Jennings, and husband of Anna Ploessel.
He began writing music at age 15, studied composition in Boston, Massachusetts, under George Chadwick. He served as a church organist in Dedham, Massachusetts (1880–82), then went on to study at the Munich Conservatory in Germany (1882–85). Later, he taught and served as a church musician in New York City (1886–93).
In 1893, his The Dream King and His Love won a prize from the National Conservatory. His oratory Hora Novissima premiered in New York in 1893, and in 1899 became the first American work to be performed at the Three Choirs Festival in Worcester, England.
Parker was organist and choir master at Trinity Church in Boston, Massachusetts (1893–1902), then Professor of Music (1894) and dean of the School of Music at Yale University (1904). He conducted the New Haven Symphony (1895–1918) and the New Haven Choral Society (1903–14), and served as organist and choir master at St. Nicholas’ Church, New York City (1902–10). He also wrote operas, Mona (1912) and Fairyland (1915) being the best known.