Joey Jo-Jo.
I recommend three books that provide excellent descriptions of the events of those first four centuries. I presume you will be able to read details online about these books:
“JESUS WARS: How Four Patriarchs, Three Queens, and Two Emperors Decided What Christians Would Believe for the Next 1500 Years” by Philip Jenkins (The Fifth-Century Political Battles That Forever Changed What the Church Teaches About the Son of God.)
“AD 381: HERETICS, PAGANS AND THE CHRISTIAN STATE” by Charles Freeman. ( In AD 381, Theodosius, emperor of the eastern Roman empire, issued a decree in which all of his subjects were required to subscribe to a belief in the Trinity of the Father, Son and Holy Spirit. This edict defined Christian orthodoxy and brought to an end a lively and wide ranging debate about the nature of the Godhead; all other interpretations were now declared heretical. Moreover, for the first time in a thousand years of Greco-Roman civilisation, free thought was unambiguously suppressed.)
“A NEW HISTORY OF CHRISTIANITY” by Charles Freeman. ( Freeman shows that there was a host of competing Christianities, many of which had as much claim to authenticity as those that eventually dominated. The imposition of ‘correct belief and an institutional framework that enforced orthodoxy were both consolidating and stifling. Uncovering the church’s relationships with Judaism, Gnosticism, Greek philosophy and Greco-Roman society, Freeman offers dramatic new accounts of Paul, the resurrection, and the church fathers and emperors.)
Doug