... what did Gutenberg do before the Bible biz? He manufactured "pilgrim mirrors." This was a hocus pocus device which was all mirror and no smoke. The mirrors were about an inch across and made of glass, mounted to a handle made of tin and lead. These mirrors were sold at holy sites to pilgrims. What you did is hold the mirror up to the holy relic of some saint (like Saint Catherine's severed index finger), and the mirror would absorb the glory of the saint's body part. (In the Middle Ages, saints were all the rage.) You could then return home and show folks the mirror which had once beheld the relic. Sort of like Polaroid but with no film.