On July 25, the Nicene Creed ("We believe in one God, the Father Almighty, Creator of all things visible and invisible...") will mark its 1700th anniversary. This is the creed that believers still recite today during liturgical celebrations. Its establishment is credited to Constantine I "the Great." Following the Edict of Milan in 313 AD, Christianity became an official religion within the two Roman Empires, ending the persecution of Christians under Diocletian. However, by 325, Constantine, now the sole emperor, faced a divided Church, fractured by various sects (Catholics, Arians, Orthodox, etc.) debating theological issues such as the divine nature of Christ and the date of Easter. These disputes threatened imperial unity.

To address this, Constantine convened a council of all the empire's bishops—1,000 from the East and 800 from the West—in the city of Nicaea, aiming to establish religious unity and prevent political discord. Due to logistical challenges, only 200 to 300 bishops attended, with two papal delegates representing the pope. The council debated key issues, including fixing the date of Easter to ensure it would never coincide with the Jewish Passover (placing it after the spring equinox), affirming the divine nature of Christ in relation to the Father (both sharing the same divine essence, known as homoousion, rejecting the idea that Christ was created by the Father), and addressing organizational matters. These included rules for baptizing heretics, prohibitions against self-mutilation, restrictions on clerics living with women, and recognizing the primacy of the bishops of Alexandria and Rome.

On July 25, approximately 300 bishops concluded the ecumenical council and celebrated Constantine's twentieth year of reign. Constantine played a pivotal role in enforcing the council's decisions, which he deemed essential for achieving unity within the Christian Church. Remarkably, the outcomes of the Council of Nicaea remain influential in the Church today, underscoring its enduring impact on faith and unity.