Did the Protestants cause the Reformation? 

Several factors led to the Reformation, including errors on the part of Protestants. But more importantly, the Church contained a plethora of errors, corruptions, and abuses, that were pervasive throughout Europe, and which contributed to a religious atmosphere in deep need of reform. Far from a religious golden age, the end of the middle ages was characterized by an orthodoxy that had gone astray and a poorly catechized laity that was riddled with syncretism. The corruption and sins of Catholics cried out to Heaven, "Arise, Oh lord!", and the Spirit came to cleanse the Church and awaken it to the gratuitousness of salvation and the futility of human efforts apart from it. The Church could have taken a conciliatory tone, that of a charitable mother, to Protestant concerns, but instead of made itself the enemy and opposition of their efforts. This only made the situation worse, and cut off many faithful Catholics from the insights the Spirit had been shedding abroad at that time.