"But when Britain with the rest of the world was recovered by Vespasian, generals became great, armies excellent, and the enemy's hopes languished. And Petillius Cerialis at once struck terror into their hearts by invading the commonwealth of the Brigantes, which is said to be the most numerous tribe of the whole province: many battles were fought, sometimes bloody battles, and by permanent conquest or by forays he annexed a large portion of the Brigantes."
Cerialis was made legate of Legio IX Hispana in Britain under Gaius Suetonius Paulinus in 60AD, just in time to be involved in the revolt of the Iceni in the winter of 60/61AD. During this uprising he tried to prevent the Icenian horde falling upon London but was forced to retreat with the tattered remains of his legion to the fortress at Longthorpe near Peterborough (Tacitus Annales xiv.32.6).
He was the legate of Legio XIV Gemina in Germany during the year of the four emperors (69AD), and was instrumental in the putting-down of the rebellion of the Batavians. His success in Germania fresh in the emperor Vespasian's mind, Cerialis was seen as the perfect choice to command the campaign against the estranged British prince Venutius, who had incited revolt among the Brigantes tribe of northern England.
He arrived in Britain with a new marine legion formed during the civil war, Legio II Adiutrix, which he stationed at Lincoln, replacing his old legion, the Ninth, from Lincoln which he moved to a new fortress at York. This done, and in command of his old legion the Ninth from York, with his second in command Julius Agricola leading the Second Adiutrix from Lincoln, he advanced his legionary forces north-westwards in a pincer movement to crush the forces of Venutius perhaps near Stanwick in Yorkshire, and thus secured the north of Britain from the Humber to Carlisle. He held the suffect consulship by 21st May 74AD (see below), so he probably left Britain after the end of the 73 campaign season.
He was born c.30AD, based on his assuming the legionary legateship in 60 and his consulship in 74. His full name as entered on a military discharge certificate or diploma from the Continent (CIL XVI 20; ILS 1992; vide infra) was Quintus Petillius Cerialis Caesius Rufus. It would appear that he was originally named (Quintus?) Caesius Cerialis, which was changed upon his adoption by Quintus Petillius Rufus. His adoptive father was possibly the Petillius Rufus who was praetor 27-28AD, and perhaps one of the four accusers of Titius Sabinus paid by Sejanus in 28AD (Tacitus Annales iii.65.1). The Quintus Petillius Rufus who was ordinary consul 83AD was very likely his son. Caesius Nasica, the legate of Legio IX Hispana c.57AD could be his elder brother (Tacitus Annales xii.40.7).