There is a conflict over the birthday of Johannes Gutenberg, inventor of a printing press that used movable type. According to Famous Birthdays, Gutenberg was born on this day in history: June 23, 1400. Wikipedia instead reports that Gutenberg was born in 1395.
Gutenberg's most famous publication is the Gutenberg Bible published in 1455. Blogger Tim Challies has written about the Gutenberg Bible in The History of Christianity in 25 Objects.