Which innovative product marketing technique was first widely used for the distribution of the Christian Bible in the 15th century?

Throughout history, religious texts have not only been spiritual guides but also remarkable products of their time. The publishing and distribution of these texts represent some of the earliest examples of product development and marketing. This trivia explores a fascinating aspect of how religious texts were developed and distributed as products that shaped civilization.

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Mass production using the Gutenberg printing press
Door-to-door subscription sales by traveling monks
Free distribution with purchase of other religious items
Early crowdfunding where communities pooled resources for copies