Having been a long time (armchair) student of Roman history, I have reached the fall of Rome and the late antiquity/early middle ages. As we all know, one cannot learn very much about this period of European history without learning about the church. What was Christianity like from the death of Jesus to Constantine's conversion? What were those early first years like for the church?
Also, could someone recommend a good book(s) about this subject?
Alrighty, first and foremost I would suggest visiting our book list, which has a nice section covering Church history. If you don’t find what you are looking for there, I would suggest a similar request for an introductory text to Christian history that was made a couple of months ago. There were some great recommendations that you should find helpful.
Now as far as a general introduction, I’ll defer to one or more of our experts in early Christian history who will be better able to address your questions. But while you wait, why not take a gander at some previous threads that got some great responses on the experience of the early Church:
•Our extensive (and much used), FAQ on the historicity of Jesus
•When did early Christians stop considering themselves to be Jews
•Early Christianity and the Pagans
•Relationship between early Christians and Rome
•Arian vs. Trinitarian Christology
•And if you’re interested in some major reading, there was a monster of an AMA a while back on Ancient Judaism and Christianity.
Hopefully, that will be enough to get you started. Happy Reading!
The Rise of Christianity by Rodney Stark is on this exact topic. It's very accessible and well written.
Do you have any specific questions about it? I don't know how to answer "What was it like?", really. It's too vague.
/u/thejukeboxhero has done you a great service in linking to our faq and previous thread.
For a general overview Rodney Stark's The Rise of Christianity is quite good, I wouldn't hesitate to recommend it. Alternatives includes Chadwick's (slightly dated but still good) The Early Church (Penguins History of the church, vol 1).
For a long and in-depth treatment, WHC Frend's The Rise of Christianity is hard to beat.
Peter Brown's stuff is top-class, although he is dealing a bit more with later antiquity, not so much with the first two centuries.
I would suggest The Underground Church by Robin Meyers.
In the second chapter, The Early Church that Never Was, Meyers paints a picture of the kind of brutality the early Christians suffered, mostly because they refused to worship Caesar. Subjects of the Roman empire were allowed to worship according to their culture, as long as they also worshipped Caesar. The early Christians rebelled against this. Meyers asserts that this anti-imperialism was the only thing Early Christians agreed on.
The Future of Faith by Harvey Cox tells a similar story, with the early Christians disagreeing heavily over the matter of Christ's divinity, but forming solidarity against the Romans.
Is that helpful?
Sounds to me like you'd enjoy The First Thousand Years: A Global History of Christianity, which I read several months ago. It really lives up to its title. Scholarly yet accessible, lacking apparent bias, truly global (as opposed to Eurocentric), and well-written with a measured pace. Highly recommended.