The Nicene Creed, formulated at the First Council of Nicaea in 325 AD and later expanded at the Council of Constantinople in 381 AD, is a foundational statement of Christian belief. It was created to address theological disputes, particularly Arianism, which questioned the divinity of Christ. The creed affirms the Trinity—the Father, Son, and Holy Spirit—as co-equal and co-eternal, emphasizing Jesus Christ’s full divinity and humanity. It remains a central declaration in many Christian denominations, though differences exist: Eastern Orthodox and Roman Catholic churches include the phrase “proceeds from the Father,” while the Catholic version adds “and the Son” (Filioque), a key theological divergence from Orthodox Christianity. This creed is important because it unites most Christian churches in their core beliefs and sets boundaries for orthodox Christian doctrine.