A version of the Marcion Evangelion is attested in the 2nd century - and that this version had the 15th year of Tiberius.
1) No gospel prior to the gospel of Luke found a need to use this date. i.e. the Jesus story is set within the time of Tiberius and Pilate. The gospels of John, Matthew and Mark finding no need to specify a date. (the linkage of Pilate and Tiberius is attested by Philo). Consequently, the Lukan author is an outlier. Why did Luke do this ? An answer to that question might shed some light on why the 15th year of Tiberius is not a date that the Marcionities would, knowingly, be interested in using. Why then is it there in the Evangelion ? Did the Marcionits, naively, decide to update the gospel in their possession without considering why Luke was so keen on this date ?
2) Luke was not without motive in using the 15th year of Tiberius for his Jesus narrative. In that introduction of the 15th year of Tiberius he lists other rulers - among them Lysanias of Abilene - an historical figure that was long dead in the 15th year of Tiberius.
https://en.wikipedia.org/wiki/Lysanias
Lysanias was the ruler of a tetrarchy, centered on the town of Abila. This has been referred to by various names including Abilene, Chalcis and Iturea, from about 40-36 BC. Josephus is our main source for his life.
The father of Lysanias was Ptolemy, son of Mennaeus, who ruled the tetrarchy before him. Ptolemy was married to Alexandra, one of the sisters of Antigonus,[1] and he helped his brother-in-law during the latter's successful attempt to claim the throne of Judea in 40 BC with the military support of the Parthians. Ptolemy had previously supported Antigonus's unsuccessful attempt to take the throne of Judea in 42 BC.
Josephus says in The Jewish War that Lysanias offered the Parthian satrap Barzapharnes a thousand talents and 500 women to bring Antigonus back and raise him to the throne, after deposing Hyrcanus[2] though in his later work, the Jewish Antiquities, he says the offer was made by Antigonus.[3] In 33 BC Lysanias was put to death by Mark Antony for his Parthian sympathies, at the instigation of Cleopatra, who had eyes on his territories.[4]
In 40 b.c. Lysanias of Abilene was involved with Jewish history, in this case with the Hasmoneans. (he was killed, in 33 b.c., by the same Roman, Marc Antony, who had the last Hasmonean King and High priest killed) Lysanias of Abilene, 40 b.c. to the 15th year of Tiberius in 29/30 c.e. is around 70 years. From the 15th year of Tiberius there is around 7 years to the death of Tiberius and the removal of Pilate from Judaea in 37 bc. A linkage back 100 years to 63 b.c. and Hasmonean history. This is why the Lukan writers had an interest in the 15th year of Tiberius. Marcionites might well have sought to update their Evangelion to the 15th year of Tiberius - but they did so at their loss. For now their gospel would forever be associated with the gospel of Luke - and thus deemed to be a late rather than an early gospel.
3) As to the Evangelion and Capharnaum: Again,the Marcionites slipped up utilizing Luke's 15th year of Tiberius - Pilate had no control over Galilee during the 15th year of Tiberius.
Capharnaum has far more relevance, inview of the Evangelion's overall narrative of a miracle worker and parable teaching philosopher, to be looked upon as an ideal place, a Camelot, a Shangri-La La, an Arcadia.
8. The country also that lies over against this lake hath the same name of Gennesareth; its nature is wonderful as well as its beauty; its soil is so fruitful that all sorts of trees can grow upon it, and the inhabitants accordingly plant all sorts of trees there; for the temper of the air is so well mixed that it agrees very well with those several sorts, particularly walnuts, which require the coldest air, flourish there in vast plenty; there are palm trees also, which grow best in hot air; fig trees also and olives grow near them, which yet require an air that is more temperate. One may call this place the ambition of nature, where it forces those plants that are naturally enemies to one another to agree together: it is a happy contention of the seasons, as if every one of them laid claim to this country; for it not only nourishes different sorts of autumnal fruit beyond men’s expectation, but preserves them a great while; it supplies men with the principal fruits, with grapes and figs, continually, during ten months of the year, (11) and the rest of the fruits as they become ripe together through the whole year: for besides the good temperature of the air, it is also watered from a most fertile fountain. The people of the country call it Capharnaum. Some have thought it to be a vein of the Nile, because it produces the Coracin fish as well as that lake does which is near to Alexandria. The length of this country extends itself along the banks of this lake that bears the same name, for thirty furlongs, and is in breadth twenty, And this is the nature of that place.
Josephus: War book 3 ch.10
Capernaum a place of healing, a place that is the ambition of nature. Is this what the author of the Evangelion had in mind when having his Jesus descent to this utopian paradise ?
4) No early gospel narrative had need for the 15th year of Tiberius. The Lukan author did have need for this date - without it he would have been unable to link his gospel narrative to Hasmonean history. The Marcionites, seemingly, were upholding their negative 'evil god' theory of the OT. If they were aware of the full implications of the Lukan usage of the 15th year of Tiberius, it's backwords look to Jewish history - they would surely run a mile....
5) The above applies to the Marcionites and their theological theories. That said, as far as I can see, there is nothing in the Evangelion that can't be viewed as being part of the developing gospel narrative. Once the linkage of the Evangelion to the gospel of Luke - and to the dating for that gospel - the door is open to placing the Evangelion back to where it belongs - the original gospel narrative - as Klinghardt is attempting to demonstrate.
(Yep, I need to update an earlier thread of mine re the gospel order - hopefully within a few days.)
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Yes, the Lukan author could have arrived at the 15th year of Tiberius (as an important year in remembering Hasmonean history) without Josephus - but he needed, because of continuing the gospel narrative, to have Pilate in Judaea in that year. Josephus gave the Lukan writer a helping hand...
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Now for some dreaming......