Historia Augusta
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The Historia Augusta, written in Latin, is a late Roman collection of biographies of the Roman emperors, their junior colleagues, designated heirs and usurpers from 117 to 244 and from 253 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 or Constantine I the Great (or even later: during the reign of Theodosius I the Great) and addressed to those emperors or other important personages in Ancient Rome. 
By the second decade of the 21st century, the consensus supported the position that there was only a single author, who wrote either in the late 4th century or the early 5th, who was interested in blending contemporary issues (political, religious and social) into the lives of the 3rd century emperors. There is further consensus that the author used the fictitious elements in the work to highlight references to other published works, such as to Cicero and Ammianus Marcellinus, in a complex allegorical game. Despite the conundrums, it is the only continuous account in Latin for much of its period and so is continually being re-evaluated. Modern historians are hesistant to abandon it as the book is possibly a source of unique information, besides its overall untrustworthiness.