Biographical details of Tacitus, widely regarded as Rome’s greatest historian, are rather sketchy. His full name was either Publius Cornelius Tacitus or Gaius Cornelius Tacitus. He was probably born about AD 56, probably into an equestrian family (the knightly class) in northern Italy or southern Gaul. It was evidently in 77 that he married the daughter of the senator Gnaeus Julius Agricola. (Immediately afterwards, Agricola began a seven-year stint as governor of Britain.) Tacitus became a senator himself. He was a celebrated orator. He was consul in 97, and in 112–113 governed the province of Asia.

The extant works of Tacitus are: Agricola (a laudatory biography of his father-in-law) and Germania, both apparently of c.98; Dialogue on Orators, probably of c.102; and, his two major works, the Histories and the Annals. These two told the story of the emperors, from the death of Augustus, in 14, to the death of Domitian, in 96. The Histories, covering the period 69–96, was evidently completed first, perhaps about 108, the Annals perhaps a decade later. Together, they are known to have comprised thirty books.[*]

There were at least sixteen books of the Annals (some scholars argue that there would have been eighteen[*]), of which the first four, part of five, part of six, part of eleven, twelve to fifteen, and part of sixteen are still extant – from a span of fifty-four years, forty years survive. It is particularly unfortunate for British history that the Claudian invasion (of 43) is included in the missing material.

A letter survives, written by Tacitus’ friend Pliny the Younger, in response to a request from Tacitus for details of the death of Pliny’s uncle, Pliny the Elder, during the eruption of Vesuvius in 79.[*] The letter begins:

Your request that I would send you an account of my uncle’s death, in order to transmit a more exact relation of it to posterity, deserves my acknowledgments; for if this accident shall be celebrated by your pen, the glory of it, I am well assured, will be rendered forever illustrious. And notwithstanding he perished by a misfortune, which, as it involved at the same time a most beautiful country in ruins, and destroyed so many populous cities, seems to promise him an everlasting remembrance; notwithstanding he has himself composed many and lasting works; yet I am persuaded, the mentioning of him in your immortal writings, will greatly contribute to eternize his name.
Pliny the Younger Letters VI, 16 (translated by William Melmoth)

Ironically, though Pliny’s letter has survived, Tacitus’ “immortal” record has not – of the Histories, only the first four books and part of the fifth, dealing with 69 and some of 70, survive.

It is not known when Tacitus died, though a date around 120 is widely supposed.

Pliny the Elder is remembered as the author of Natural History, a thirty-seven book encyclopedia. In 79 he was prefect of the fleet at Misenum, on the Bay of Naples.
All dates in this article are AD/CE. (See Anno Domini.)
St Jerome (d.420), in his ‘Commentary on Chapter 14 of Zechariah’: “Cornelius Tacitus too, who wrote the Lives of the Caesars in thirty books from Augustus to the death of Domitian.”
Ronald Mellor, in Tacitus’ Annals (2010), Chapter 1, writes: “Tacitus probably shaped the Annals into three hexads – blocks of six books. The first six books cover the reign of Tiberius, and the second hexad also closes with the death of an emperor, Claudius.”