First: trying to date when Marcion lived. Some hints show he may have lived earlier than commonly thought (around 145CE). Justin Martyr, in his First Apology (around 150CE), wrote:
http://www.earlychristianwritings.com/t ... ology.html
That sounds like a man with a long career: an old man ('even at this day alive') who has spread his message to 'many of every nation'.
Also, Clement of Alexandria, in his Stromata Book 7 (around 180 CE):
http://www.earlychristianwritings.com/t ... book7.html
According to the Church Fathers, Marcion apostatised at some point in his career. It seems that he was born later in the First Century, perhaps around 80CE if he was an older man in the 150s CE. He is grouped with early heretics like Valentinus. If Marcion was born in Pontus, then he might have had early exposure to letters by Paul sent to the Christian community of the Galatians.
The start of Marcion's Evangelion is:
1. In the fifteenth year of the reign of Tiberius Caesar,
2. [Pontius Pilatus being the Governor of Judaea,] Jesus came down to Capernaum, a city in Galilee, and was
3. teaching on the sabbath days: and they were astonished at his doctrine: for his word was in authority.
I don't think it unreasonable to conclude, based on what we know about Marcion, that Marcion thought that this really happened. I.e. that there really was a Jesus who went to Galilee and taught Jews there his doctrine. That it wasn't some analogy for a greater truth.
Since Marcion also had access to an early version of Paul's letters, I suggest that he didn't think Paul had a different Jesus in mind to that Gospel's Jesus. That is, for Marcion, Paul's Jesus also came to earth in the 15th year of Tiberius, into Galilee, and taught on the sabbath days.
So if Marcion's Gospel was the first one written, then it is the earliest conciliation of the Gospel and Paul's letters in terms of an earthly and actual Jesus.
Some notes:
1. For the above, I'm assuming that Marcion's Gospel is the first written Gospel.
2. I'm not assuming Marcion himself wrote the first Gospel. It may be that an earlier writer may have made a literary story about a Jesus who looked like a man who descended from heaven that wasn't meant to be literal, and Marcion did take it literally. But I suggest that this pushes back the date of when Paul's letters about Jesus Christ were seen as referring to the same person as the Gospel's Jesus Christ.
3. We don't really know when Marcion apostatised. But he appears to have been active early in the Second Century CE, and the earliest person to reference both a Gospel and letters of Paul.
Any thoughts on the above?