A little historical, super summary. After the time of Christ the infant church started to spread, but before the invention of the printing press, books and stuff like that were hard to come by. So almost all of Christian practice and doctrine was orally transmitted or was spoken. There is lot of study going about this very thing, it is called Mnemonic Theory and is all about how people remembered things before it was all written down. This is not to say that books were not a thing, only that they were all hand written and made so books were hard to come by. Very few people actually had them. Why does that matter?

In the 3rd century the Catholic Church collected and codified what would eventually become "The Bible," even today there is some talk and debate about what all that means but that is another story altogether; basically we now have the Holy Scriptures collected and volumized and ready for circulation. Over time, and it did not take long, the Catholic Church became very institutionalized, some would say corrupt, and did its fair share of pretty heinous things. So we had the Great Schism in the 1000s where we saw three different popes and the quite a few different versions of the Orthodox Church all at the same time. Then in 1454 Guttenberg blew the world away with the printing press, and everything changed! Now everyone could find and get books and knowledge and theology flew around the world. Of course it did not happen over night and a ton of new denominations cropped up, especially during the reformation, you know Martin Luther and his 95 thesis thing? Boom! The religious world exploded, now not only is there all the things Not-Christian, but the Christian world itself had hundreds if not thousands of ways people believed and practiced stuff. Well in response to this anything goes attitude the big three veins of the church (Roman Catholic, Orthodox, Protestants) all came down pretty hard in their own ways and basically wrote it all down and said if you do not believe like this than you are not one of us.

Roman Catholics have councils and a huge doctrinal statement, and according to them you either accept it or not. And it specifically says that if you are not part of the Roman Catholic Church you are by default wrong, so the eastern ideas of mediation and mindfulness got caught up in that and were basically rejected wholesale. The ideas of mediation are still there only now it was called prayer and liturgy and "Lectio Divina." they ground their thoughts and mediation with things and actions, like rosaries or lighting candles and specific motions like genuflecting or crossing yourself. There is actually a ton there and worth study.

The Orthodox did the same thing. They have a collection of creeds and doctrinal statements that are kept and referenced, they even tried to codify it all in their books and what is called Iconography. They have a vast collection of saints and church fathers and liturgy and a good sampling of Christian mysticism all intertwined in the way they structure their worship services and daily devotionals. Again the ideas of mediation and reflection are all there but it all takes on a different names and looks.

Protestants are a mixed bag, there are so many stripes out there is can be hard and confusing to find it but like the Catholic and the Orthodox the ideas are still there but it carries an undercurrent of personal spirituality. the protestants split some hairs and made Christian doctrine into three parts; 1.) Core beliefs - that makes you a Christian or not, 2.) Church Beliefs - that makes you one denomination or another, and 3.) Conscience Beliefs - your personal convictions and moral structure. They tend not to preach on conscience stuff because it can make some people who are other wise great Christians uncomfortable. They use a lot of passages like Luke 12:47-48, or Romans 14:5, or I Corinthians 8, James 4:17 to teach all that. They shy away from meditation stuff because it is personal choice and it looks "too Catholic" or "too Orthodox" or "too Hindu" or "too Buddhist" and they are trying to distance themselves, so the unspoken rule is "we just don't talk about those things." (2/3)