Jesus Christianity to get off the ground, apart from Judaism it had to please lots of people holding diverse beliefs. To gain ascendency it had to encompass among other cults, the Roman favourite Mithras.
In Mithraism the blood of the Savior, the Great Shepherd, was commemorated by an annual ritual of partaking of symbolic bread (or cakes) and wine well before christianity adopted it. The symbolism of blood to the Romans was cleansing and strength and at the initiation ceremony the novice was placed under a grill in the dark Mithraeum (subterranean windowless church) and the hot blood from a dying sacrificial bull rained down on him some of which he was obliged to drink as it fell.
Inscribed in the Mithraic temple which occupies the catacombs under the Vatican today is the pre-Christian text, "Whosoever does not drink of my body and eat of my flesh, the same will not be with me in paradise".
So I agree with you Crazyguy that for the sake of harmonisation of the Jewish religion with its monotheism and blood prohibition, and the other competing cults, the early Jesus movement had to make many compromises. It is most interesting to see how the two divergent views on blood were accommodated. The Jew would still be offended by drinking blood but the Roman would accept the idea from familiarity.
Paul did a sterling job in the letter to the Hebrews to rationalise the different strands of dogma.
Without the Jesus myth and Constantine's mother Helena having adopted the cult, the dominant Roman religion would probably have ended up in a Dionysian mould...but this cult too had to be absorbed for Jesus Christianity to become the catholic or universal faith, Dionysus contributing the expression "The true vine", he turned water into wine at a wedding feast, was born a virgin son of God and was crucified for the sake of sinful mankind. Makes you think!