The Secret History of Procopius tr. by Richard Atwater [1927]

Procopius, who also wrote a mainstream military history and a toadying description of the monuments which Justinian built, had to keep his most acute writing for posthumous publication. This text flays Justinian and Theodora as corrupt, immoral, and just plain evil. Even though the account sounds fantastic, it is considered genuine by modern historians (but not necessarily accurate). Of course, the Eastern Orthodox Church considers Justinian a saint, so you'll either love or hate this book.

The original title of this work was Anecdota, which means (as far as I can tell) 'things not given over, withheld.' I can say that there are a few anecdotes here which fall into the realm of the fantastic. Procopius speculates that Justinian might have been something . . . not even human, perhaps vampiric. He soberly quotes eyewitness accounts of Justinian shapeshifting into a 'shapeless mass of flesh,' and literally losing--and retrieving--his head (p. 132). It sounds just like a modern horror movie special effect. . . . In another place, the translation has Justinian killing a 'trillion' people. The text actually says "A myriad myriads of myriads" (a myriad is the highest number in Greek, 10,000). [By my reckoning, that is 10^5*3 = 10¹⁵ = 100,000,000,000,000, or 100 trillion.] All of this is a bit sophistical of course, what Procopius obviously means here is "a ridiculous number."

The artistic san-serif 'Procopius' typeface was first used to typeset this book. A sample page can be found here.