His name also appears in some sources as Zadoc. The Genealogical Record of the Barnum Family calls him Ladoe Barnum, which appears to be a typographical or transcription error.
In the records of the Congregational Church of New Fairfield appears the notation, "Zadoc Barnum & Mercy his wife, Confession for Sin of Fornication, July 29, 1763."
Zadok served in the Revolutionary War, in Colonel Nehemiah Beardsley's 16th Regiment, under Captain Peter Penfield.
The US Census of 1790 shows Zadok Barnum, with one other free white male 16 years and upwards, three free white males under 16 and seven free white females, living in New Fairfield, Fairfield County, Connecticut.
Other sources show his death as occurring in 1806.