Sourced guide
Apostolic succession explained simply
Apostolic succession is the claim that the church's public teaching and ministry continue from the apostles through bishops. This site separates strict episcopal succession from broader transmission by teaching, citation, correspondence, and influence.
The strict meaning
In the strict Catholic and Orthodox sense, succession is bishop-to-bishop continuity in an apostolic see or wider episcopal line.
That is why the Bishops page only shows bishops grouped by city and ordered chronologically.
The broader transmission view
The homepage graph is broader. It includes teaching, correspondence, citation, opposition, ordination, baptism, and other historically meaningful links.
That broader view is useful for learning. The strict episcopal view is useful when the question is formal succession.
Relevant relationships
Ignatius wrote a personal letter to Polycarp en route to Rome; Polycarp in turn forwarded the corpus of Ignatian letters to the Philippians (Phil 13).
Forward edge into the next era. Irenaeus in his Letter to Florinus describes hearing Polycarp preach in his youth at Smyrna.
Irenaeus describes in his Letter to Florinus hearing Polycarp preach in his youth in Smyrna and remembering his testimony about John the Apostle. This is direct first-person testimony.
Tertullian (De Praesc. 32) says Clement was ordained by Peter. Origen and others identify him with the Clement of Phil 4:3. No first-person testimony survives — marked tradition per the brief.