Saint Athanasius (c. 296–373) was a renowned Christian theologian and Bishop of Alexandria, best known for his staunch defence of the Nicene Creed and his opposition to Arianism, a heresy that denied the full divinity of Jesus Christ. As a key figure in the early Church, he played a crucial role in preserving orthodox Christian doctrine during the 4th century. Athanasius was exiled multiple times for his beliefs but remained unwavering in his commitment to the truth of the Trinity. His theological writings, particularly his On the Incarnation, have had a lasting impact on Christian theology. He was canonized as a saint and is celebrated for his courage and theological insight.

The Canadian Conference of Catholic Bishops (CCCB) has decreed that this is a Holy Day of Memorial to be observed in Canada.