Early Church heresies refer to beliefs and teachings that deviated from the established doctrines of the Christian Church in its formative years. These heresies often arose as various groups interpreted the teachings of Jesus and the Apostles differently, leading to conflicts over core beliefs such as the nature of God, the Trinity, and the role of Jesus as both divine and human. Some notable heresies included Arianism, which denied the full divinity of Christ, and Gnosticism, which emphasized secret knowledge for salvation. The Church responded to these challenges through councils, such as the Council of Nicaea in 325 AD, which aimed to clarify and unify Christian doctrine.