The question of "History" - that there is an objectively-true, evidenced account of the past: of how things came to be the way they are now - is one that has been very strong since the subject of History began to emerge as a distinctive discipline, detached (supposedly!) from religious (later ideological) justifications and dishonesties.
But the idea that true history emerges from "the evidence" turns-out to be as false as the analogous argument for the natural sciences; in both cases coherence and proof is provided by theory, and theory is an must come prior to evidence.
(Because without a prior theory; how would anyone what what counted as evidence, its relative value compared with other evidence, or what a piece or collection of evidence meant?).
In mainstream culture this has left us with two false and incoherent alternatives.
On the one hand, multiple rival blustering and categorical assertions that This is The Truth about history - assertions that ignore the dependence on prior theory.
And on the other side the supposedly radical "relativist" subversion that states "everything is ideology" so that objective truth has no meaning, so that truth cannot be known and is just a consequence of power - assertions that ignore their blatant self-subversion.
For these folk; History is just a story made-up by the winners, and the discipline of History something created to reach the conclusions they have already-decided - and any other story can have equal validity.
And that is pretty much how things stand.
The traditionalist, orthodox, religious reactionary side wrongly assert that the evidence for their assertions is objective; and the radical, liberal, "reforming" side of religion asserts that their own take on the world is better than that of the conservatives; despite that they have previously asserted that "better" has no objective meaning and is merely a consequence of power.
Usually, people "pick a side" because they can see no alternative, and in order to join a gang; and stoutly continue to ignore the fatal weakness, the non-objectivity of their own position, its dependence on theoretical assumptions; by relentlessly focusing on the fatal weakness and non-objectivity of their opponents position.
The choice that culture forces upon us is between "truth is what I say" and "there is no truth" - both based on circular and incoherent arguments!
What should we do when faced with two false alternatives?
Should we do what most people do when confronted by mainstream electoral politics, or rival sports teams located in your home city: just pick a side then support it fanatically - while demonizing the opposition.
Is that really the best we can do when confronted by the most fundamental problems of our human existence?
People need to recognize that the dilemma is one of our own creation, and rooted in an unexamined assumption that the truth about reality is and must-be public and shared information.
The false modern dilemma of choosing between two falsehoods, arises from our own built-in assumption that truth is either located externally and communally and has nothing to do with me - my job being only to choose to submit to it; or else "truth" is nothing-but inside my head... whatever my brain happens to be telling me at this instant.
What we need is obvious enough - we need to understand how truth both depends on me and my assumptions and thinking; and truth also is about reality, about things (entities) other than myself.
I think the distinction we need is between things existing, and knowledge about them. We must assume - and indeed are born assuming - that other entities exist.
Doubt about the reality of reality emerge later, and indeed are large distinctive to relatively modern times (the past few centuries). These doubts are reinforced by the impossibility of finding "evidence" that other entities exist outside of our own thoughts about them.
On the other side; the blustering assertions of the reality of reality are nearly-always actually assertions about our knowledge of reality.
For instance, religious people are not content to assume the objective reality of God as another entity from "me"; but combine this with asserting the objectivity of their own claim for knowledge of God's attributes.
Thereby re-entering the false-dilemma debate that undermines all such claims; after which the conservative religious will bluster and shout his knowledge-assertions, while the radical religious will adopt a passive aggressive strategy of undermining possibility of any knowledge about reality - to distract from the fact he is making his own assertions concerning reality, and assuming these assertions are more-true than the conservative's.
To loop back - how can we take account of History in such a situation; when we assume that there was a real history that led up to the present, but all our specific knowledge of that history is undermined by the subjective-objective distinction!
When History has become Impossible!
Especially this is a problem in that Christianity is located in History; and takes place at a particular past time and place.
When History has become impossible in the mainstream of public discourse - this must (and does) have a profoundly subversive effect on Christianity.
Christians can neither depend on "objective History" nor can they allow History to be wholly personal and subjective.
The answer? Well, because the insoluble problem is located in the domain of public discourse, and the phenomenon of consensus; then the Christian cannot root his religion in public discourse.
And cannot means cannot - because insofar as he does root religion in public discourse, his religion Will Be subverted - as we see all around us.
And public discourse includes all churches.
My conclusion is that the historical religion of Christianity now cannot be rooted-in churches, cannot derive-from churches, cannot be "what a church says".
And that "cannot" means cannot.