Greek historian, the author of a universal history Bibliotheca historica.
He lived in the time of Julius Caesar and Augustus and his own statements make it clear that he travelled in Egypt during 60-57 BC and spent several years in Rome. The latest event mentioned by him belongs to the year 21 BC.
His history consisted of 40 books and was divided into three parts.
- The first treats of the lenic tribes to the destruction of Troy;
- the second ends with Alexander´s death;
- and the third continues the history as far as the begining of Caesar´s Gallic War.
Of this extensive work there are extant only the first five books, treating of the mythic history of the Egyptians, Assyrians, Ethiopians and Greeks;
and also the 11 th to the 20th books inclusive, beginning with the Greco-Persian War of 480-479 and ending with the history of the successors of Alexander before the partition of the Macedonian Empire (302).
The rest exists only in fragments preserved in Photius and the excerpts of Constantine Porphyrogenitus.
The Bibliotheca invaluable where no other continous historical source has survived is of considerable value, too as supplying to some extent the loss of the works of earlier authors, from which it was compiled.
Diodorus does not always quote his authorities but in the books that have survived his most important sources for Greek history were certainly Ephorus (for 480-340 BC) and Hieronymus of Cardia (for 323-302).
In particular sections (e.g. for Sicily, or the reign of Alexander) Diodorus followed special authorities who cannot always be named for certain. For chronology he used probably Apollodorus of Athens and Castor of Rhodes and for geography Megasthenes (at second hand?), Agatharchides and Artemidorus.