Historiaster

Humbly inscribed to those two celebrated historiasters, Mr. [John] Oldmixon, author of the History of the royal House of Stuart, &c. &c. &c. and Mr. Samuel Chandler, author of the late History of persecution.

Source: wiktionary

A human sacrifice is here clearly indicated. This mysterious cavern, with its diabolical associations, […] leave an impression which the efforts of those historiasters who endeavor to whitewash Tiberius cannot weaken with all their arguments.

Source: wiktionary

We next meet our historian—or historiaster, if the name might be coined to describe him—on one of the comparatively rare occasions where he is dealing mostly with undisputed facts.

Source: wiktionary

Speaking of a series of trials for treason held at Antioch, of which he [Ammianus Marcellinus] does not recollect all the grim details, he excuses himself with the words: "As the full particulars of what was done have escaped my memory, I shall describe succinctly what I can recall to mind." "But this is shocking," some scientific historiaster of our own day will exclaim. "There must have been an official record of the trial; he should have consulted that." The answer is, of course, that under that iron despotism Ammianus had as much chance of inspecting official documents of state trials as a German scholar in the last decade would have had of perusing the secret archives of the Gestapo.

Source: wiktionary