Ignatius of Antioch

Bishop of the great church at Antioch, where believers were first called Christians, Ignatius was arrested under Trajan and marched across Asia Minor to be executed in Rome. Along the road he wrote seven letters to the churches that met him — urgent, affectionate appeals for unity around the bishop, warnings against division and false teaching, and a startling eagerness for martyrdom as the way to "attain to God." His letters are among the earliest Christian writings outside the New Testament, and they show a church already centered on the Eucharist and the person of Christ.

He is the first known Christian writer to use the phrase "the Catholic Church" (katholike ekklesia).