When you read about what is history, oftentimes it's mentioned that it is not a chronicle of events. But isn't it really just that?
History is also is a matter of highly debatable possibilities and probabilities. Some important events so chronicled may never have happened, and some important events that did happen are not chronicled. Underpinning any event and its date there must be historical evidence - hopefully primary sources of evidence. This evidence however is mute. I does not talk and tell the historian what it is. The historian evaluates this evidence. There is an evaluation process ...
The historian needs to tell the truth and nothing but the truth.
The historian must also be prepared to deal in hypothetical truth - in possibilities and probabilities.
The stringent drive for objectivity via trusted historical methods does not leave any room for bias, prejudice or subservience to an agenda. So really it's just a chronological event record. New data gets studied on how it fits into this chronicle.
Evaluation of the evidence may differ between historians. What causes the difference in the evaluation of the same evidence may include stuff like "bias, prejudice or subservience to an agenda". It may also include the failure to take into account related evidence which some historians may not have studied, or for example primary evidence that is literary but in another language.
Also new data may rewrite the chronological order of events.
The historian's narrative is based more on how grammatically nice the flow of his story is.
"But I have good reason to distrust any historian who has nothing new to say or who produces novelties, either in facts or in interpretations, which I discover to be unreliable. Historians are supposed to be discoverers of truths. No doubt they must turn their research into some sort of story before being called historians. But their stories must be true stories. [...] History is no epic, history is no novel, history is no propaganda because in these literary genres control of the evidence is optional, not compulsory.
~ Arnaldo Momigliano, The rhetoric of history, Comparative Criticism, p. 260
On Pagans, Jews and Christians:
Arnaldo Momigliano, 1987
p.7
One is almost embarrassed to have to say
that any statement a historian makes must
be supported by evidence which, according
to ordinary criteria of human judgement,
is adequate to prove the reality of the
statement itself. This has three
consequences:
1) Historians must be prepared to admit
in any given case that they are unable
to reach safe conclusions because the
evidence is insufficient; like judges,
historians must be ready to say 'not proven'.
2) The methods used to ascertain the value
of the evidence must continually be scrutinised
and perfected, because they are essential to
historical research.
3) The historians themselves must be judged
according to their ability to establish facts.
The form of exposition they choosen for their presentation
of the facts is a secondary consideration. I have of course
nothing to object in principle to the present multiplication
in methods of rhetorical analysis of historical texts.
You may have as much rhetorical analysis as you consider
necessary, provided it leads to the establishment of the
truth - or to the admission that truth is regretfully
out of reach in a given case.
But it must be clear once for all that Judges and Acts,
Heroditus and Tacitus are historical texts to be examined
with the purpose of recovering the truth of the past.
Hence the interesting conclusion that the notion of forgery
has a different meaning in historiography than it has in
other branches of literature or of art. A creative writer
or artist perpetuates a forgery every time he intends
to mislead his public about the date and authorship
of his own work.
But only a historian can be guilty of forging evidence
or of knowingly used forged evidence in order to
support his own historical discourse. One is never
simple-minded enough about the condemnation of
forgeries. Pious frauds are frauds, for which one
must show no piety - and no pity.