Little is known of his early career. An inscription reveals he was involved in the suppression of a slave revolt in Apulia during the reign of Tiberius, probably in 24, alongside Marcus Aelius Celer. He was suffect consul for the second half of 29, and held a provincial governorship, probably of Pannonia, in the early years of Claudius's reign: another inscription shows he oversaw the building of a road between Trieste and Rijeka at this time.
Claudius appointed him to lead his invasion of Britain in 43, in support of Verica, king of the Atrebates and an ally of Rome, who had been deposed and exiled. The army is believed to have been composed of four legions, the IX Hispana, then in Pannonia, the II Augusta, the XIV Gemina and the XX Valeria Victrix, plus approximately 20,000 auxiliary troops. The II Augusta was commanded by the future emperor Vespasian. Three other men of appropriate rank to command legions are known to have been involved in the invasion: Vespasian's brother Titus Flavius Sabinus and Gnaeus Hosidius Geta appear in Cassius Dio's account of the invasion; Gnaeus Sentius Saturninus is mentioned by Eutropius, although as a former consul he may have been too senior, and perhaps accompanied Claudius later.
On the beaches of northern Gaul Plautius faced a mutiny by his troops, who were reluctant to cross the Ocean and fight beyond the limits of the known world. They were persuaded after Claudius's freedman and secretary Narcissus addressed them: seeing a former slave in place of their commander, they cried "Io Saturnalia!" (Saturnalia being a Roman festival in which social roles were reversed for the day) and the mutiny was over.
The invasion force sailed in three divisions, and is generally believed to have landed at Richborough in Kent. The Britons, led by Togodumnus and Caratacus of the Catuvellauni, were reluctant to fight a pitched battle, relying on instead on guerrilla tactics. However, Plautius defeated first Caratacus, then Togodumnus, on the rivers Medway and Thames. Togodumnus died shortly afterwards, although Caratacus survived and continued to be a thorn in the invaders' side.
Having reached the Thames, Plautius halted and sent for Claudius, who arrived with elephants and heavy artillery and completed the march on the Catuvellaunian capital, Camulodunum (Colchester). A Roman province was established in the conquered territory, and alliances made with nations outside direct Roman control, some of which were placed under the control of a loyal native king, Cogidubnus. Plautius became governor of the new province until 47, when he was replaced by Publius Ostorius Scapula. On his return to Rome and civil life, Plautius was granted an ovation, during which the emperor himself walked by his side to and from the Capitol.
Plautius's wife, Pomponia Graecina, remained in mourning for forty years after the execution of her kinswoman Julia by Claudius and Messalina, in open, and unpunished, defiance of the emperor. In 57 she was charged with a "foreign superstition", usually taken to mean conversion to Christianity. According to Roman law, she was tried by her husband before her kinsmen, and was acquitted.
Another Aulus Plautius, probably his son, was allegedly the lover of Agrippina the younger, and was murdered by Agrippina's son Nero. Quintus Plautius, who was consul in 36, was probably his younger brother. Plautius was probably the uncle whose "distinguished service" saved Plautius Lateranus from the death penalty in 48 after his affair with Messalina. By the time Lateranus was eventually executed, in 65, for his part in a conspiracy against Nero, his uncle was probably dead and could no longer help him.
- Anthony R Birley (1981), The Fasti of Roman Britain, pp. 37-40
- Cassius Dio Cassius, Roman History 60:19-22; Suetonius, Vespasian 4; Eutropius, Abridgement of Roman History 7:13
- Tacitus, Agricola 14
- Dio Cassius, Roman History 60:30.2; Suetonius, Claudius 24
- Tacitus, Annals 13.32
- Suetonius, Nero 35.4
- Tacitus, Annals6.40
- Tacitus, Annals 11:36, 15:60