Cassius Dio - Roman History

Dio published a Roman History (Historia Romana), in 80 books, after 22 years of research and labour. The books cover Roman history for a period of approximately 1,400 years, beginning with the arrival of the legendary Aeneas in Italy (c. 1200 BC), through to the subsequent mythistoric founding of Rome (753 BC); they also cover historical events up to AD 229. The work is one of only three written Roman sources that document the Celtic revolt of AD 60 - 61 in Britain that was led by Boudica. Until the 1st century BC, Dio provides only a summary of events; after that period, his accounts become more detailed. From the time of Commodus, Dio is very circumspect in his conveyance of the events that he witnessed.

In the 21st century, fragments remain of the first 36 books, including considerable portions of both the 35th (on the war of Lucullus against Mithridates VI of Pontus) and 36th (on the war with the pirates and the expedition of Pompey against the king of Pontus) books. The books that follow, up until the 54th, inclusive, are nearly all complete; they cover the period from 65 BC to 12 BC, or, from the eastern campaign of Pompey and the death of Mithridates to the death of Marcus Vipsanius Agrippa. The 55th book contains a considerable gap, while the 56th to the 60th books (which cover the period from 9 to 54), inclusive, are complete and contain the events from the defeat of Varus in Germany to the death of Claudius. Of the 20 subsequent books in the series, there remain only fragments and the meager abridgement of John Xiphilinus, a monk from the 11th century. The abridgment of Xiphilinus, as now extant, commences with the 35th book and continues to the end of the 80th book (it is a very indifferent performance and was made by order of the emperor Michael VII Parapinaces). The last book covers the period from 222 to 229 (the reign of Alexander Severus).

The fragments of the first 36 books, as have been collected, consist of four kinds:

1. Fragmenta Valesiana: Such as those that were dispersed throughout various writers, scholiasts, grammarians, and lexicographers, and were collected by Henri Valois.
2. Fragmenta Peiresciana: Consists of large extracts, found in the section entitled, "Of Virtues and Vices", contained in the collection, or portative library, compiled by order of Constantine VII Porphyrogenitus. The manuscript of this belonged to Peiresc.
3. The fragments of the first 34 books, preserved in the second section of the same work by Constantine, entitled “Of Embassies.” These are known under the name of Fragmenta Ursiniana, as the manuscript in which they are contained was found in Sicily, Italy, by Fulvio Orsini.
4. Excerpta Vaticana by Angelo Mai: Contains fragments of books 1 to 35 and 61 to 80. Additionally, fragments of an unknown continuator of Dio (Anonymus post Dionem), generally identified with the 6th-century historian, Peter the Patrician, are included; these date back to the time of Constantine. Other fragments from Dio that are primarily associated with the first 34 books were found by Mai in two Vatican MSS.; these contain a collection that was compiled by Maximus Planudes. The annals of Joannes Zonaras also contain numerous extracts from Dio.