What is the significance of the Nicene Creed in Trinitarian doctrine?

The Nicene Creed, established in 325 AD, is a pivotal document in affirming Trinitarian theology. It serves to unify believers by articulating essential beliefs about Christ's divine nature and His relationship to the Father. The Creed emphasizes that the Son is 'begotten, not made, of the same essence as the Father,' thereby reinforcing the doctrine that while the persons of the Trinity perform distinct roles, they are united in essence and purpose. This formulation was particularly significant in countering heresies like Arianism, which denied the full divinity of Christ, thus safeguarding the orthodox understanding of the Trinity throughout church history.