Athanasius of Alexandria was a prominent Christian theologian and bishop in the 4th century. He is best known for his strong defense of the doctrine of the Trinity and his opposition to Arianism, a belief that denied the full divinity of Jesus Christ. Athanasius played a crucial role in the formulation of the Nicene Creed during the First Council of Nicaea in 325 AD. Throughout his life, Athanasius faced multiple exiles due to his beliefs and conflicts with various Roman emperors. He authored several important works, including "On the Incarnation," which articulates the significance of Christ's divine nature. His contributions greatly influenced Christian theology and established him as a key figure in the early Church.