Excerpts from the Wikipedia article:

Saint Irenaeus (Greek: Εἰρηναῖος), (2nd century AD – c. 202) was Bishop of Lugdunum in Gaul, then a part of the Roman Empire (now Lyons, France). He was an early church father and apologist, and his writings were formative in the early development of Christian theology. He was a hearer of Polycarp, who in turn was a disciple of John the Evangelist.
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During the persecution of Marcus Aurelius, the Roman Emperor from 161-180, Irenaeus was a priest of the Church of Lyon. The clergy of that city, many of whom were suffering imprisonment for the faith, sent him in 177 to Rome with a letter to Pope Eleuterus concerning the heresy Montanism, and that occasion bore emphatic testimony to his merits. While Irenaeus was in Rome, a massacre took place in Lyons. Returning to Gaul, Irenaeus succeeded the martyr Saint Pothinus and became the second Bishop of Lyon.

That he was a bishop in Lyon circa 180 C.E., means (1) Christianity by that time was pretty widespread, such that (2) there were not only churches in Lyon, but (3) so many churches, that they needed a bishop. Constantine won’t show up as Emperor yet for another 126 years. Constantine cannot have invented Christianity.

Scholars contend that Irenaeus quotes from 21 of the 27 New Testament Texts:

Matthew (Book 3, Chapter 16)
Mark (Book 3, Chapter 10)
Luke (Book 3, Chapter 14)
John (Book 3, Chapter 11)
Acts of the Apostles (Book 3, Chapter 14)
Romans (Book 3, Chapter 16)
1 Corinthians (Book 1, Chapter 3)
2 Corinthians (Book 3, Chapter 7)
Galatians (Book 3, Chapter 22)
Ephesians (Book 5, Chapter 2)
Philippians (Book 4, Chapter 18)
Colossians (Book 1, Chapter 3)
1 Thessalonians (Book 5, Chapter 6)
2 Thessalonians (Book 5, Chapter 25)
1 Timothy (Book 1, Preface)
2 Timothy (Book 3, Chapter 14)
Titus (Book 3, Chapter 3)
1 Peter (Book 4, Chapter 9)
1 John(Book 3, Chapter 16)
2 John (Book 1, Chapter 16)
Revelation to John (Book 4, Chapter 20)


What a list. 126 years prior to Constantine’s advent as Emperor. He cannot have invented Christianity’s scriptures, nor can he have invented Christianity.

P.

“What I admire is honesty and truth, no matter who, or what, the sources are.”
— Uri Yosef