Life in the middle ages for ordinary people?

Christianity in particular arose out of the Roman period when most people were trying to figure out the nature of the universe in lieu of any scientific evidence.

When Christianity was coming into being there were innumerable religious sects throughout the Roman world, all competing with each other. By chance Christianity was the sect that grew, but the reason people believed in it was because it was an answer.

In the modern world educated people take scientific knowledge for granted, in the ancient world this understanding did not exist, it was inconceivable. Without the ability to come to an accurate understanding people developed mythology.

the "high middle ages" were a period of considerable social change and relocation of population groups. It was the growth of the cities and the establishment of a large merchant class that provided for the growth of religion. The farmer tilling his soil had better things to do than contemplate God, a merchant sitting at home at the end of a day after the ledgers are closed would have little else to do.

In our earliest records of European civilisation in the middle ages religiosity is at the front and centre of everyday lives. This world is a pale shadow of the coming world. The coming world was the determinate ordering of being for everyday Europeans. There was no "turn" to religion. Religiosity was the central moment of being.

(Sources: Monestary records, physical architecture of churches, spread and spacing of churches in the social nexus, survived church decorations and sermons, canon law).

Religion did not wither but grew. The popularity of mass participatory religious movements, involving both retreats from society, or attempts to purchase the future world in the current demonstrates this.

(Sources: Debate on indulgences, Beguines and Beghards's records and stories, Pizan's writings, mass religious uprisings prior to protestantism).

I don't think your theory really holds up to much examination. There's just a huge amount more at work than people having a lack of better entertainment.

Religion 'took hold' long before the high middle ages. In essence, wherever you find civilization, you find religion, and that religion accrued great power to itself from the earliest times. It wasn't for lack of entertainment, but far more complex processes in human society, not least the fact that religious people thought it deserved to have that power. It's a sort of chicken and egg thing. Religion was important because people thought it should be. Why did they think it should be? Because they were religious. There is no point at which non-religious people existed who felt differently. Before the 19th century at the earliest, religion is simply a constant of human existence.

If you want to specifically talk about the medieval church, it's power and influence grew at the same time as government grew and what we would recognise as the major European kingdoms and principalities began to develop (by the standards of the day) 'centralized' administrations.

For the Norman monarchs of England and Scotland, for instance, there were great benefits to giving lands, power and influence to monastic houses, as they settled the land with friendly supporters who shared their cultural outlook, and who would develop often remote territory and bring it under something closer to centralised control. But the kings were also genuine Christian men who believed that granting land and power to the Church had spiritual benefits for themselves and their family. It wasn't just a cynical power play.

Your mistake is also in thinking that churchgoing by 'ordinary' people was terribly important in the medieval world. They weren't. Most people may have only attended church a few times a year - Easter, maybe Christmas - and the presence of peasants in the pews was not viewed as the most important work of the church, by any means. Real power lay with the bishops and monastic houses, and in the land they held, and the thousands of people in holy orders. These created what might be viewed as 'medieval prayer factories'. Millions of monastic masses and prayers carried out the 'serious' religious side of the church, but also provided employment and sustenance for a the more wealthy part of society.

Christianity 'took hold' in the medieval period (by which I think you really mean 'grew more rich and powerful') because it offered a wide range of advantages to the European rulers and the aristocratic classes. 'Ordinary' people were religious a) Because they always had been b) were Christian because they had no choice - that was the only option on offer from their aristocratic overlords.

A more interesting question might be - just how religious WERE the peasant classes. A look at Emmanuel Le Roy Ladurie's 'Montaillou' might be a place to start, although there's probably a mountain of more recent research out there on the subject.

As it's been already stated, we lack good sources from medieval times that wouldn't come from people of the Church (who surely wouldn't write about such things) or traveling merchants (who didn't have enough local knowledge).

This way I'll go with the source from 1543, which is a book by Mikołaj Rej, called "A Brief Discussion among Three Persons: a Lord, a Commune Chief and a Priest". Maybe this will help you somehow.

Unfortunately I have no idea where to get English translation of it, and translation software won't help you, as it's written as Old-Polish language poetry.

In this work, three representatives of different states speak about their rights and problems with other states. As it's really a long thing, I'll translate some parts that would be crucial for your topic - the beginning of Commune Chef speech, when he's asked by a Lord what he thinks of the Priest, who is accused by a Lord of being lazy and greedy:

My lord, we're just a simple folk, What can we know about it, poor souls? We can only believe that it's in our best interest, Whatever he says during his lectures. (context: we don't know much about religion, we're just told what to do)

After those words he speaks of how the Church takes more and more money from the poor, while the Priests don't teach them much about the God itself. But let's go further to his summary of the quarrel between a Lord and a Priest:

A Priest blames a Lord and the Lord blames a Priest, While for us, simple people, the problems come from both of them. (context: so we really don't care about it)

Just take it into account that the writer was not only a politician, but also Calvinist and his works reflect his understanding of the Catholic Church.