Sometimes, someone else's answer is bad and needs correction, like Vince LaRue on why the Catholic Church was powerful in Middle Ages

Q

3 reasons why the Christian Church was powerful in Europe Medieval times?
https://www.quora.com/3-reasons-why-the-Christian-Church-was-powerful-in-Europe-Medieval-times

Vince LaRue

Church-Planting Missionary to Chile

Answered 39m ago

There’s really only one reason needed. What you refer to as the “Christian Church” was actually the Roman Catholic Church, and it was powerful because it exercised absolute power over the lives and souls of every human being under its domain. They held sway over the consciences of the masses, which they wielded to coerce monarchs to comply with their wishes.

They were powerful because everyone believed that the wine-headed bachelor in Rome could send them to Hell if they didn’t obey. That’s quite persuasive (especially when no one can read and you get burned at the stake for having a Bible).

Hans-Georg Lundahl

Just now

“They held sway over the consciences of the masses, which they wielded to coerce monarchs to comply with their wishes.”

In other words, the countries were Christian and therefore the rulers could not be very openly anti-Christian, most of the time.

"They were powerful because everyone believed"

In other words, you admit there were no Protestants back then. How can then Protestantism be the Church of Christ in face of the promise in Matthew 28:20?

"that the wine-headed bachelor in Rome"

Bachelor he was most of the time.

Wineheaded, you might want to document it, is the word means "drunkard". I am actually not quite familiar with the word, first time I hear it.

"could send them to Hell"

Well, his predecessor St Peter could define what you did and did not need to do to get saved.

"if they didn’t obey"

That was not the condition exacted. Disobeying the Pope is usually, but not always, sinful.

"That’s quite persuasive (especially when no one can read ..."

False.

"... and you get burned at the stake for having a Bible)."

True for a restricted number of countries for a restricted number of centuries and even then to the full only in a restricted area known as England.

In Belgium, where there was a Spanish Inquisition, owning a French mistranslation of the Bible by the reformers could get the "Bible" (if you call it that) on a bonfire but definitely not sufficient to get yourself there.

For instance, Tyndale was well known to have made a Bible translation in English by the Spanish Inquisition in Belgium, and even so it took them 7 years to prove him guilty of heresy.

Other

and better answer:

William Laraque

former New England Business Delopment Officer at Export-Import Bank of the United States (2006-2009)

Answered 1h ago

Because Christianity preserved civilization with the help of Charlemagne and a few monks on isolated islands before Gutenberg and social media. Read Kenneth Clark’s “Civilization,” Charles Adams’ “Mont Saint-Michel and Chartres.” Read!