You can go right to the direct source. Martin Luther, did just what you are asking for when he wrote his 95 Theses and nailed them to the Church Door, kick-starting the Protestant reformation. [here’s a list](https://www.luther.de/en/95thesen.html) TL:DR, the catholic church was a corrupt place that exchanged favors with priests for “divine salvation”. These were called “indulgences”, and lots of people didn’t like it, so they left and made their own churches.
For effects, it obviously split the Church irreparably, leading to the large number of Christian denominations separate from catholicism and orthodoxy. But there are other effects.
The causes were that society was changing, but Catholic church tried to prevent change. So some countries chose their own religion.
Back then religion was not just about where you go on Sunday morning, or attitude to couple issues. It was a way of life.
Catholic church has built a strict autocratic hierarchy: Pope speaks for the God, Kings are appointed by Pope, local nobles are appointed by King. If you disagree with your rulers, you disagree with God. This divine order is perfect, and any change is heresy.
But people were getting richer and more educated, so they demanded more control of their life and more accountability from rulers. Respect for Catholic church was reduced by corruption and scandals and lengthy wars between its subjects states.
So when some priest came out saying that there is room for reform in the church, plenty of people were willing to listen, including the rich and the powerful.
Here is more reading on causes:
https://en.wikipedia.org/wiki/History_of_Protestantism#Roots
And a summary of consequences:
https://en.wikipedia.org/wiki/Reformation#Consequences_of_the_Reformation
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