The Bishops that were well known at that Time
1 After Antoninus had reigned seven years and six months, Macrinus succeeded him. He held the government but a year, and was succeeded by another Antoninus. During his first year the Roman bishop, Zephyrinus, having held his office for eighteen years, died, and Callistus received the episcopate.
2. He continued for five years, and was succeeded by Urbanus. After this, Alexander became Roman emperor, Antoninus having reigned but four years. At this time Philetus also succeeded Asclepiades in the church of Antioch.
3. The mother of the emperor, Mammæa by name, was a most pious woman, if there ever was one, and of religious life. When the fame of Origen had extended everywhere and had come even to her ears, she desired greatly to see the man, and above all things to make trial of his celebrated understanding of divine things.
4. Staying for a time in Antioch, she sent for him with a military escort. Having remained with her a while and shown her many things which were for the glory of the Lord and of the excellence of the divine teaching, he hastened back to his accustomed work.
Source: Church History (New Advent)