The printing press was invented by Guttenberg in 1439. Before the existence of this invention, copying texts was a hard work that was done mainly by monks and nuns in monasteries.
Luther's Reformation began with publication of the Ninety-five Theses by Luther in 1517 and it meant the start of a schism in Western Christianity. The existence of the printing press allowed to transmit Luther criticism to Catholicism much faster and to soon gather many supporters that created churches following Luther's principles.
