Polycarp of Smyrna
Saint Polycarp (AD 70-156) was Bishop of Smyrna in Asia Minor. After 86 years of serving Christ the Lord, he laid down his life for Him in a heroic martyrdom by the Romans. His Letter to the Philippians  gives a good indication of what Catholic Christianity was like at the time. He knew Ignatius of Antioch who was also martyred.
"Our chief sources of information concerning St. Polycarp are: (1) the Epistles of St. Ignatius; (2) St. Polycarp's own Epistle to the Philippians; (3) sundry passages in St. Irenæus; (4) the Letter of the Smyrnaeans recounting the martyrdom of St. Polycarp."