Bart Ehrman was the Chair of the Religion Dept. at UNC-Chapel Hill when he wrote the following two books:
Lost Christianities: The Battles for Scripture and the Faiths We Never Knew
The early Christian Church was a chaos of contending beliefs. Some groups of Christians claimed that there was not one God but two or twelve or thirty. Some believed that the world had not been created by God but by a lesser, ignorant deity. Certain sects maintained that Jesus was human but not divine, while others said he was divine but not human.
In Lost Christianities, Bart D. Ehrman offers a fascinating look at these early forms of Christianity and shows how they came to be suppressed, reformed, or forgotten. All of these groups insisted that they upheld the teachings of Jesus and his apostles, and they all possessed writings that bore out their claims, books reputedly produced by Jesus's own followers. Modern archaeological work has recovered a number of key texts, and as Ehrman shows, these spectacular discoveries reveal religious diversity that says much about the ways in which history gets written by the winners. Ehrman's discussion ranges from considerations of various "lost scriptures"--including forged gospels supposedly written by Simon Peter, Jesus's closest disciple, and Judas Thomas, Jesus's alleged twin brother--to the disparate beliefs of such groups as the Jewish-Christian Ebionites, the anti-Jewish Marcionites, and various "Gnostic" sects. Ehrman examines in depth the battles that raged between "proto-orthodox Christians"--those who eventually compiled the canonical books of the New Testament and standardized Christian belief--and the groups they denounced as heretics and ultimately overcame.
Scrupulously researched and lucidly written, Lost Christianities is an eye-opening account of politics, power, and the clash of ideas among Christians in the decades before one group came to see its views prevail.
Misquoting Jesus: The Story Behind Who Changed the Bible and Why
For almost 1,500 years, the New Testament manuscripts were copied by hand––and mistakes and intentional changes abound in the competing manuscript versions. Religious and biblical scholar Bart Ehrman makes the provocative case that many of our widely held beliefs concerning the divinity of Jesus, the Trinity, and the divine origins of the Bible itself are the results of both intentional and accidental alterations by scribes.
In this compelling and fascinating book, Ehrman shows where and why changes were made in our earliest surviving manuscripts, explaining for the first time how the many variations of our cherished biblical stories came to be, and why only certain versions of the stories qualify for publication in the Bibles we read today. Ehrman frames his account with personal reflections on how his study of the Greek manuscripts made him abandon his once ultra–conservative views of the Bible.
These next two books reveal important information about the early Church. The first is about Constantine and the bishops at the time of the writing of the creeds. The second is about happenings about 200 years later:
When Jesus Became God: The Struggle to Define Christianity during the Last Days of Rome
The life of Jesus, and the subsequent persecution of Christians during the Roman Empire, have come to define what many of us know about early Christianity. The fervent debate, civil strife, and bloody riots within the Christian community as it was forming, however, is a story that is rarely told. Richard E. Rubenstein takes readers to the streets of the Roman Empire during the fourth century, where a divisive argument over the divinity of Jesus Christ was underway. Ruled by a Christian emperor, followers of Jesus no longer feared for the survival of their monotheistic faith, but they found themselves in different camps—led by two charismatic men—on the topic of Christian theology. Arius, an Alexandrian priest and poet, preached that Jesus, though holy, is less than God, while Athanasius, a brilliant and violent bishop, saw any diminution of Jesus' godhead as the work of the devil. Between them stood Alexander, the powerful Bishop of Alexandria, in search of a solution that would keep the empire united and the Christian faith alive.
Jesus Wars: How Four Patriarchs, Three Queens, and Two Emperors Decided What Christians Would Believe for the Next 1,500 years
In this fascinating account of the surprisingly violent fifth-century church, Philip Jenkins describes how political maneuvers by a handful of powerful characters shaped Christian doctrine. Were it not for these battles, today’s church could be teaching something very different about the nature of Jesus, and the papacy as we know it would never have come into existence. Jesus Wars reveals the profound implications of what amounts to an accident of history: that one faction of Roman emperors and militia-wielding bishops defeated another.
Finally, here's an entertaining and informative book to read. I'm listing it here because it gives a good introduction to the writing and writers of the Gospels.
Desire of the Everlasting Hills: The World Before and After Jesus
How did an obscure rabbi from a backwater of the Roman Empire come to be the central figure in Western Civilization? Did his influence in fact change the world? These are the questions Thomas Cahill addresses in his subtle and engaging investigation into the life and times of Jesus.
Cahill shows us Jesus from his birth to his execution through the eyes of those who knew him and in the context of his time—a time when the Jews were struggling to maintain their beliefs under overlords who imposed their worldview on their subjects. Here is Jesus the loving friend, itinerate preacher, and quiet revolutionary, whose words and actions inspired his followers to journey throughout the Roman world and speak the truth he instilled—in the face of the greatest defeat: Jesus' crucifixion as a common criminal. Daring, provocative, and stunningly original, Cahill's interpretation will both delight and surprise.
Re reincarnation, early Christians clearly believed in it and many still do today. Some sources say that there was at least one, maybe two, papal encyclical(s) denouncing reincarnation as a heresy. Other sources say that there was no such encyclical. The online list of encyclicals only goes back to about the 13th century, so there's no easy way to determine which side is correct. There's also an ongoing discussion (pro and con) on what the Bible says about reincarnation. The Bible conveniently supports both sides.
My personal opinion: Many early Christians (and some still today) believed in reincarnation, and it wasn't in the Church's interest to support that belief. Whether or not there was an encyclical, the belief was certainly suppressed by the Church. Vestiges of the belief can be found in the Bible, although interpretations vary.
