Pope Alexandros of Alexandria was the 19th Patriarch of Alexandria, serving during the early 4th century. A priest during the persecutions under Emperors Galerius and Maximinus Daia, he later ascended to the patriarchate following the death of Achillas. He is primarily remembered for his leadership in addressing theological crises, most notably the rise of Arianism and disputes regarding the calculation of Easter. As a central figure at the First Council of Nicaea, he worked to defend Trinitarian orthodoxy and mentored his successor, Athanasius, who became a prominent Church Father.