feb 11, 1440 - Invention of printing press
The printing press was invented by Johannes Gutenberg, and soon became one of the most significant devices in spreading the ideas/concepts on thoughts of religion, politics, etc. in Europe for centuries to come. The reliable/effective nature of the printing press allowed it to become apart of a more philosophical group, since it could be used to print large quantities of religious texts in Latin or in vernacular languages, changing the groupings for followers and disclosing its relevnce to the AP theme (OS).
Added to timeline:
AP Euro Timeline - Metelski