Library Eusebius of Caesarea Life of Constantine
Book 4, Chapter 38: How the Market-Town of Gaza was made a City for its Profession of Christianity, and received the Name of Constantia.
For in fact the place now called Constantia, in the province of Palestine, having embraced the saving religion, was distinguished both by the favor of God, and by special honor from the emperor, being now for the first time raised to the rank of a city, and receiving the more honored name of his pious sister in exchange for its former appellation.
English translation by Ernest Cushing Richardson, in Nicene and Post-Nicene Fathers, Series II, Vol. I (eds. Philip Schaff and Henry Wace; Buffalo: Christian Literature Publishing Co., 1890). Public domain. Digital text via New Advent Church Fathers.