detailed account
Note from 'The Destruction Wrought By A Demon Emperor' chapter from 'The Secret History by Procopius

It is impossible to say how many lives were lost during Justinian's reign. Gibbon thought that the number might have approached a hundred million. Procopius's million million (literally ten thousand times ten thousand times ten thousand) is no more intended to be taken literally than is St John's ten thousand times ten thousand, and thousands of thousands, or the thousands of ten thousands of Rebekah's progeny.