Hermann Dessau in the context of "Prussian Academy of Sciences"

The Historia Augusta (English: Augustan History) is a late Roman collection of biographies, written in Latin, of the Roman emperors, their junior colleagues, designated heirs and usurpers from 117 to 284. Supposedly modeled on the similar work of Suetonius, The Twelve Caesars, it presents itself as a compilation of works by six different authors, collectively known as the Scriptores Historiae Augustae, written during the reigns of Diocletian and Constantine I and addressed to those emperors or other important personages in Ancient Rome. The collection, as extant, comprises thirty biographies, most of which contain the life of a single emperor, but some include a group of two or more, grouped together merely because these emperors were either similar or contemporaneous.

The true authorship of the work, its actual date, its reliability and its purpose have long been matters for controversy by historians and scholars ever since Hermann Dessau, in 1889, rejected both the date and the authorship as stated within the manuscript. Major problems include the nature of the sources that it used, and how much of the content is pure fiction. For instance, the collection contains in all about 150 alleged documents, including 68 letters, 60 speeches and proposals to the people or the senate, and 20 senatorial decrees and acclamations.