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 development of early Christian theology and was a key figure at the Council of Nicaea in 325 AD. Born around 296 AD in Egypt, Athanasius became the Bishop of Alexandria in 328 AD. He faced multiple exiles due to his beliefs and conflicts with various Roman emperors. His writings, including the famous "On the Incarnation," have had a lasting impact on Christian thought and continue to be studied today.