Agricola in Britain, recounted by Tacitus
https://en.wikipedia.org/wiki/Agricola_(book)

and see:
https://en.wikisource.org/wiki/Agricola
https://en.wikipedia.org/wiki/Gnaeus_Julius_Agricola
https://www.romanobritain.org/3_bio/bio_agricola.php
https://www.roman-britain.co.uk/people/julius-agricola/#battle-of-mons-graupius
https://www.youtube.com/watch?v=U7Wywl2Oc1Y (40+ minute YouTube)
https://historiamag.com/the-victories-of-agricola

The history of Roman Britain is spotty at best.  Only parts of it were preserved in any surviving Roman reporting, and, as noted in our previous discussions, there never were any written reports by the Briton Celts.  We don't even know the names or accomplishments of many of those Romans who were appointed to the Governorship of the British Province. 

<--- Roman Governor Agricola, statue emplaced on a terrace in 1896 overlooking the Great Bath at the spa in Bath England.  Labeled "Agricola" but there's no contemporary clue of how he really looked .

We do have, however, good Roman reporting on the tenure of one of the most important and successful appointees, Gnaeus Julius Agricola, who seems, also, to have been the longest serving Roman Governor of Britain.  In 77 AD, Agricola was appointed Governor of the Britania Province by Emperor Vespasian. (He and Vespasian had served at the same time in Britain under Gaius Suetonius Paulinus, and both Vespasian and Agricola had successfully commanded legions in Britain.) 

Agricola had supported Vespasian in the "Year of the four emperors" and Vespasian had won that contest.  Agricola's rewards for his support were command of a legion and later was the governorship of Britain, which lasted until the death of Vespasian, through the short reign of Vespasian's elder son Titus, and into the beginning of Domitian's reign.  But ---

Flavian Dynasty --->

Agricola was recalled to Rome by Vespasian's second son, Domitian, 84/85 AD during Domitian's reign as the third and last member of the Flavian Dynasty.  Everyone thought that Domitian, suffering  from insecurity, feared Agricola as a possible rival:  Agricola was gaining too much popularity for his British accomplishments, during his "abnormally long term", and Domitian thought that has own accomplishments in Germany were sufferring  in comparison. 

Appointees as Roman provincial Governors usually served about two years -- patronage jobs lasting any longer would restrict the Emperor's ability to spread the wealth among possible eligiblePatricians (and, later, eligible Equestrians).

Every Governor would envy one that might have a panegyrist on his staff, and it might get even better if that writer was a son-in-law.  Agricola's daughter was married to the Roman historian and politician Publius Cornelius Tacitus, who, today, is recognized as one of the most accurate, least biased historians of his time.

Among the earliest writings of Tacitus, one of his shorter works, was Da vita et moribus Iulii Agricolae. (On the life and character of Julius Agricola, published ca. 98 AD, after Domitian was safely dead, he having been assassinated in 96 AD.)  For more on what is commonly known as "The Agricola" see https://en.wikipedia.org/wiki/Agricola_(book).

A full English translation of "The Agricola" is on the Internet at https://en.wikisource.org/wiki/Agricola.

When Agricola was finally recalled to Rome, after his long term as Governor, he quietly retired from public life and died, some said under suspicious circumstances, in 93 AC, five years before Tacitus's "Agricola" came out.  The book quickly became known as a panegyric, a praising, some said over the top, eulogy.

Agricola's story:
Agricola (AD 40-93) was the only Roman general who could claim to have subdued the whole of Britain.  A Roman general is known by his victories -- by his triumphs and honors. 

<--- Publius Cornelius Tacitus.  What we know about Agricola, aside from a few inscription for corroboration, comes from the Tacitus eulogy/ biography/travelogue/anthopology study of the Briton Celts.

Tacitus almost certainly was with Agricola on campaign in Britain (at least for three or so years?).  There is still academic warfare about how far his descriptions can be trusted, but when the Agricola was produced there were still witnesses alive who could debunk any falsehoods or exaggerations. 

So Agricola came to Britain more often and stayed longer than any other Roman.  He was there from 58 until 60 AD as a tribune, probably in Legio II Augusta, seconded to the Governor's Staff during his campaigns in Wales.  Then he returned to Rome and a civilian career until the end of the civil war of 69 AD (Year of the Four  Emperors).  Following that, he was named by victorious Emperor Vespasian as the new commander (and successful reformer) of the rebellious Legio XX Valeria Victrix and joining the northern campaigns of Governor of Britain, Quintus Petillius Cerialis.  Agricola led that legion from 70 until 73 AD. 

In 77 AD he was sent back to Britain again by Vespasian as Governor for an unprecedented extended tour from 77 AD until relieved by Domitian in 84. That made a total of at least thirteen years on British battlefields, more than any other Roman.

In the first instance, according to Tacitus, Agricola participated, as a Military Tribune on the staff of Suetonius Paulinus, in the 60 AD suppression of the Druids in northern Wales.  Sites including sacred oak groves Druidic where rites including Wicker Man human sacrifices took place.  Then the Romans crossed to Anglesy (Mona) Island where they finally extirpated the influence of the Briton Druids.

<--- Put a framed "Fine Arts" print of this John Harris Valda imagination of the Romans storming ashore on Mona Island for only $64 at https://fineartamerica.com/featured/the-roman-attack-on-anglesey-john-harris-valda.html.

The attack on Mona, interrupted, but then resumed and completed by Agricola years after the eastern Briton Boudicca revolt, is viewed as a turning point in the Roman military occupation.

Tacitus wrote in his later book, the Annals, 14.37, talks of the methods of Suetonius Paulinus (who Tacitus clearly despised: "the [Roman] troops gave no quarter even to the women: the baggage animals themselves had been speared and added to the pile of bodies.  The glory won in the course of the day was remarkable and equal to that of our older victories: for, by some accounts, little less than 80,000 Britons fell at a cost of some 400 Romans killed.

In the interlude of the eastern Iceni Briton revolt Paulinus did not get back east soon enough able to save his legion that he had left in garrison or to prevent the Destruction of Colchester, London, and St. Albans.  But he did eventually and viciously quell the revolt.  Agricola is thought to have participated in that effort.

After quelling the Iceni revolt, Paulinus was relieved for using excessive force.

At some point during the times of the Welsh/Anglesey operations and the suppression of the Iceni revolt, Agricola interacted with Vespasion, whose own mission, successfully accomplished, had been to bring southwest Britain under Roman control.

In 70 AD Agricola was called up again to fight in Britain.  His first job was  to suppress a mutiny of the XX Legion.  After bringing the legion back into line and given command  of the XXth, Argicola, Then he joined (according to Tacitus) the then Roman occupation Governor of Britania, Petilius Cerialis, in bloody battles against the largest and then most powerful Celtic Briton tribal alliance, called for convenience the Brigantes, who controlled central Britain.  Cerialis split the Roman occupation armies into two columns and gave command of the western column to Agricola.  Both columns then worked their way north pushing the Brigantes ahead of them.  On reaching Carlisle, Agricola crossed back eastward through Stainmore Pass and with Cerialis brought the Brigantes to battle and neutralized them.  The battle is thought to have occurred at a stronghold called Stanwick Camp, an Iron Age hillfort.  Agricola was again demobilized having participated in two successful campaigns in Britain (both of which  memorialized by Tacitus).

Agricola was the called up once more by Vespasian in 77/78 AD to be the Governor of the Province (Legatus Augusti pro praetore -- Britain was an imperial rather than a senatoria province and home of four Legions).  During his tenure, until 83/84 AD, he significantly expanded Roman control through his military campaigns in Wales, northern England, and souhern Scotland, culminating in the victory over the Caledonian tribes at the Battle of Mons Graupius.  He also focused on consolidating Roman rule by promoting infrastructure, Roman style towns, and education to Romanize the local population, an important policy that was documented by Tacitus.