I’ve recently encountered the claim that Christianity was not very common in Jerusalem and the other surounding areas where Jesus lived and taught in the early centuries of the Church. Is this true? What would be some good resources for learning about the spread of early Christianity, something I know very little about beyond what is in the Bible?
Well Antioch, was first where they were called Christians.
When Saul started rooting out Christians after the stoning of Steven they fled northward. When Saul was encountered to continue the killing is when he encountered Christ.
The New Testament consists primarily of the Writings to the churches set up in modern day Turkey/Greece and of course Rome.
It was these areas Christianity was able to grow.
The Jews in Jerusalem also had their own turmoil culminating in the destruction of the temple in AD 70 and the subsequent dispersal of the Jews too.
Jesus brought in the New Covenant, and history clearly demonstrates that as Jerusalem and Judaism changed figuratively over night and has never returned to how it was.
I would encourage you to read the church fathers, such as Ignatius of Antioch, Clement of Rome, Irenaeus, Justin Martyr, and others. These all wrote in the first century after Christ and give lots of insights.
The bishops I listed wrote letters to the churches just like Paul’s.