From the LCMS website:
Athanasius was born in Alexandria in Egypt in A.D. 295. He served as a church leader in a time of great controversy and ecclesiastical disagreements. At the Council of Nicaea in 325, he defended Christian orthodoxy against the proponents of the Arian heresy, which denied the full divinity of Jesus Christ. During his 45-year tenure as bishop of Alexandria, Athanasius wrote numerous works that defended the orthodox teaching. His enemies had him exiled five times; on two occasions he was almost murdered. Yet Athanasius remained steadfast and ended his days restored fully to his church responsibilities. The Athanasian Creed, though not composed by Athanasius, is named in his honor because it confesses the doctrinal orthodoxy he championed throughout his life.