The Council of Nicaea, held in 325 AD, was significant in defining key aspects of Christian doctrine. Convened by Emperor Constantine I, it aimed to address the Arian controversy regarding the nature of Christ and his relationship to God. The resulting Nicene Creed affirmed the divinity of Christ, establishing foundational beliefs for Christianity. The council also standardized key practices within the church, such as the calculation of Easter. By promoting unity among Christian factions, the Council of Nicaea played a crucial role in shaping the early church's doctrine and organizational structure, influencing Christian theology for centuries to come.