Upon reading the introduction by R. T. Bond, which comes before my cherished Father Brown omnibus I came across an interesting fact: Chesterton mentions Father's Brown's first name in two different places, and they are different each time!
1. Our beloved priest detective is referred to as "the reverend J. Brown". This may give a connection to Father John O'Connor, who inspired G.K. Chesterton to write of an outwardly insignificant man whose real character did not match his external appearance.
2. Flambeau once calls Father Brown "Paul". "Paul" originally meant "little" which would seem to point to Father Brown's wonderful humility.