From the OHS PC Database, derived from A Guide to North American Organbuilders, by David H. Fox (Richmond, Va.: Organ Historical Society, 1991, rev. ed. 1997, with updated information). -

John Duncan Brennan was born May 3, 1853 in Boston, Massachusetts. He was with the George Ryder firm of Boston, Massachusetts, by 1896, as foreman. White succeeded Ryder in Brennan, Gleason & White of Boston, a partnership of former Ryder employees which dissolved shortly thereafter. Brennan then opened and operated his own firm for approximately 25 years. He died July 3, 1921 in Reading, Massachusetts.

Sources:

• The Boston Organ Club Newsletter: 118:4.
• Peter T. Cameron.
• The Diapason, August 1921, 12.
• Local directories of the period.
• Barbara Owen, The Organ in New England (Raleigh: Sunbury Press, 1979), 398.
• Elizabeth Towne Schmitt.