What document standardized Christian beliefs?

The Nicene Creed, formulated in 325 AD during the First Council of Nicaea, is a key document that standardized Christian beliefs. It was created to address and unify various theological disputes, particularly concerning the nature of Christ and his relationship to God the Father. The Creed affirmed foundational Christian doctrines such as the Trinity and the divinity of Jesus, serving as a definitive statement of faith for many Christian denominations.