Apostolic Father (within life of the Apostles)
Disciple of John
Martyr in the Coliseum
Wrote 7 preserved letters to the Churches that reveal:
1)  early theology on the sacraments
2)  three “offices” bishops / elders/ deacons
3)  ecclesiology (Greek root word meaning “assembly, called out ones”, church leadership, church role in salvation, church discipline etc).