Suetonius is hardly a reliable source. It's so relied upon by historians mainly because him and Tacitus are the only authors whose work covering the full I century CE have survived.
Had he lived today, he'd write gossip for tabloids or disreputable websites; his "greatest hit" in Antiquity together with his "Lifes of the Twelve Caesars" (
Vita Caesarum) is a (lost) "Lifes of Famous Prostitutes", so you get an idea. His only other work to have survived is
De viris illustribus, another collection of biographies of artists and writers. He also wrote about the most disparate subjects, both in Latin and Greek:
Peri ton par' Hellesi paidion (about games in Greece),
Peri blasphemion (on insults) and a series of works dealing with the aspects of Roman life:
On Roman Dress,
On Roman Festivals,
On the Roman Year, etc.
Also, his sources are not clear at all. We know he wrote during the reign of Hadrian because another dubious source, the
Historia Augusta (HA), says so:
"
(Hadrian) removed from office Septicius Clarus, the prefect of the guard, and Suetonius Tranquillus, the imperial secretary, and many others besides, because without his consent they had been conducting themselves toward his wife, Sabina, in a more informal fashion than the etiquette of the court demanded."
This is supported also by the dedication of the
Vita Caesarum to his friend Septicius Clarus who was Praetorian Prefect in 119 CE (as confirmed by the HA). The text itself also supports this chronology, as the biographies stop with Domitian. Nerva is left out because he was the "step-grandfather" (if that's even a word) of the ruling
augustus Hadrian, and Suetonius had to be careful about offending the ruling dynasty. And given what he liked to write about, he would have offended them all for sure.
We don't know which were his sources, but we know some details about his life because he was a friend of senator Pliny the Younger, who in turn was one of the
amici of emperor Trajan, and reached high posts in the administration of the empire during his reign. Pliny the Younger has left a very extense collection of letters, in which he talks about Suetonius more than once, describing him as a quiet man, devoted to books. But Suetonius himself never was a senator, nor did he occupy any real posts of influence, except when at the end of Trajan's reign, thanks to the influence of his friend Pliny he was appointed to three posts that could have allowed him access to important imperial documents:
- (Secretary) ab epistulis latinis to the emperor (in charge of writing down the official letters of the emperor redacted in Latin).
- (Secretary) a bibliothecis, responsible of the public libraries in the Urbs.
- (Secretary) a studiis, which is usually assumed by historians to have meant that he was in charge of the imperial archives.
If the later assumption is true, then Suetonius had access to the
Sancta Sanctorum of historical evidence, the wet dream of any historian, and so it's beyond infuriating that he squandered such golden opportunity by writing a collection of gossipy tales dealing mostly with the sexual misdemeanors of the twelve
augusti that preceded Nerva. Besides, it's been proved by modern historical research that he just accepted uncritically whatever he found in the archives or in the unnamed sources he used (very common in ancient authors, just think of the strambotic tales included in Pliny the Elder's works).
For example, in the "Life of Vespasian", he copied
verbatim the official version of Vespasian's childhood and youth that the Flavians had made available for public consumption. But in her biography of this emperor, modern historian Barbara Levick offered convincing evidence to show that things were quite different in the Flavians' household during Vespasian's early years from what Suetonius wrote.
And similar examples can be found for most of the biographies in Suetonius' work. This means that a critical approach is indispensable when dealing with this (and other) ancient sources. Suetonius did not want to write an erudite collection of biographies for the use and comfort of future historians. He wanted to write an entertainment with an historical background. In this sense, it could be said that it's not an "historical" work at all, but rather a
divertimento for the amusement of Roman literati at the expenses of the first twelve
augusti.
