Answer
The most pious Augustus was a title given to Constans by Athanasius in his eulogy. Athanasius was a bishop of Alexandria who was exiled by Emperor Constantius II. He later returned to Alexandria after Constantius' death and delivered a eulogy for Constans, who had been killed by the usurper Magnentius. In his eulogy, Athanasius praised Constans for his piety and his support of the Nicene Creed.