Origen (~230)
nSuccessor to Clement as head of the Christian school in Alexandria, Origen later moves to Caesarea, where he develops the largest Christian library in antiquity.
nOrigen gives some insight into the status of the canon question in his time.  He notes that two categories were commonly recognized by the orthodox:
nBooks acknowledged by all Christians (21)
n4 Gospels, Acts, 13 Paul, 1 Peter, 1 John, Revelation
nBooks disputed by some Christians (10)
nHebrews, James, 2 Peter, 2-3 John, Jude,
nPs-Barnabas, Hermas, Didache, Gospel of Hebrews