Ignatius matters because he stands remarkably close to the Apostolic age.
While traveling toward martyrdom in Rome, the bishop of Antioch wrote letters to Christian communities.
Those letters give us a window into Christianity near the beginning of the second century.
What Do We Find?
In his letter to Smyrna, Ignatius speaks about:
- a bishop;
- presbyters;
- deacons;
- unity around the bishop;
- Baptism;
- the Eucharist;
- the "Catholic Church."
He also attacks a group that rejects the reality of Christ's flesh and says they abstain from the Eucharist because they do not confess it as Christ's flesh.
Read the Primary Source
Ignatius, Letter to the Smyrnaeans, especially chapters 7--8:
https://www.newadvent.org/fathers/0109.htm
Another Letter: One Eucharist
Writing to the Philadelphians, Ignatius urges Christians toward one Eucharist, one altar and unity with the bishop, presbytery and deacons.
https://www.newadvent.org/fathers/0108.htm
What Does This Establish?
It does not establish that every administrative feature of twenty-first-century Catholicism existed unchanged in AD 107.
It does establish that extremely early Christianity could already be described using categories that include:
bishop + presbyters + deacons + Eucharistic unity + visible Church.
The Question
If Ignatius walked into my church this Sunday, what would he recognize --- and what would surprise him?