Saint Alexander, whose feast day is celebrated today, died on April 18, 328 AD, and is recognized as one of the pivotal figures in church history for his defense of true faith during a period when Arian heresy ravaged many Christian territories and communities. He served as the Patriarch of Alexandria and is best known for his significant role at the First Council of Nicaea in the 4th century, which has been acknowledged by various Christian denominations beyond the Catholic Church, including the Orthodox Churches, the Assyrian Church of the East, the Anglican Church, and the Lutheran Church.

During Alexander's tenure in the early 4th century, a cristological debate emerged within the Alexandrian church, prominently featuring Priest Arius, who enjoyed considerable popularity among the populace. Arius's teachings posited that while Jesus was perfect in essence, he was merely a created being of the Father and thus subordinate to Him. He rejected the notion of the Father and Son being of the same substance, arguing instead that Jesus was similar but not identical to the Father.

The conflict between Alexander and Arius highlights the theological divisions of that era, with Alexander firmly upholding the orthodox view of the Trinity against Arianism. This battle shaped the future of Christian doctrine and established a foundational understanding of Christ's divine nature, which remained influential in Christian theology for centuries to come.