Though the builder of this instrument is not known for certain, internal evidence suggests that it is the work of J. G. Pfeffer, and it appears to date from 1865. The projecting keydesk and the action date from the 1904 Kilgen rebuild, which was undertaken to "modernize" the organ, according to church records. Originally, the instrument had folding doors covering a recessed keydesk. The organ case and frame are designed to accept a second division, but there are no signs that the organ has. ever had more than one division. A plywood top was installed over the case in the 1975 renovation. An unpublished dissertation on the organ has been written by Richard Haas. * According to The Organ Handbook by Hans Klotz, published by Concordia Publishing House, St. Louis, in 1969, " ... the 'Calcant' (Kalkantenruf) ... signals to the person in charge of treadling or cocking the bellows ... "
-- Information from 1979 OHS Handbook

Since the above publication it has been determined that the organ was probably relocated from Trinity Lutheran, 4th Street, St. Louis, c. 1865 by Pfeffer and not originally built by the Pfeffer firm.