So I understand that the Council of Nicaea establishes a date for Easter, and attempts to establish a single understanding of the divine nature of Jesus. Some time in the first century, Paul is summoned to Jerusalem for a council over his teachings to gentiles - specifically, over the issue of circumcision. In Catholic school, all we learned of the Christian experience between these two events are a few facts (painted with a really broad brush) about the martyr experience.

I have a lot of questions that arise about the diversity of Christian belief before Nicaea. Were there any practical differences in rituals and practices that caused the Christian community to call a council between these two events? Were there Christian heresies that the community punished internally? Were there any movements that drove the religious practice of Christianity?

Thank you to any who take interest in these questions!