I’m reading Meredith Lake’s fascinating ‘cultural history’ The Bible In Australia.
I can’t recall ever encountering the word ‘colporteur’ before, but Lake in referring to the activity of agents of a variety of societies that were dedicated to the distribution of Bibles and religious literature uses the label Colporteur.

A variety of online dictionaries define a Colporteur as:

• a person who travels to sell or publicize Bibles, religious tracts, etc.
• a peddler of books.

This reminds me of Big Dan Teague, the morally compromised Bible salesman from O Brother, Where Art Thou.