Publius Ostorius Scapula (died 52) was a Roman statesman and general who governed Britain from 47 until his death, and was responsible for the defeat and capture of Caratacus.

Publius Ostorius Scapula was the son of a Publius and likely the nephew of Quintus Ostorius Scapula, the first joint commander of the Praetorian Guard appointed by Augustus and later prefect of Egypt. The Quintus Ostorius Scapula who was consul in 41 AD was probably his brother or cousin.^[1]

Nothing is known of his early career. He was suffect consul, probably in 46. In the winter of 47 he was appointed the second governor of Roman Britain by the emperor Claudius, succeeding Aulus Plautius. The south and east of the island was securely occupied and alliances had been made with tribes outside the Roman-controlled area, but other tribes continued to resist. Believing a new governor would be reluctant to campaign so late in the year, they staged attacks and uprisings.

Ostorius disabused them of this notion and responded vigorously, attacking relentlessly and allowing the native resistance no time to regroup. He apparently (based on an emendation of a corrupt passage in Tacitus's Annals) declared his intention to disarm all the Britons south and east of the rivers Trent and Severn. The geographical area described has led to discussion about the role of the Fosse Way as a desired frontier line during the period, as it links the Trent and the Severn.

The Iceni, a tribe based in Norfolk who had not been conquered but allied themselves with the Romans voluntarily, objected to this plan and led neighbouring tribes in an uprising. Ostorius defeated them by storming a hill fort, possibly Stonea Camp in the Fens near March in Cambridgeshire, in a hard-fought battle. His son, Marcus Ostorius Scapula, won the corona civica for saving a Roman citizen's life during the fighting. The Iceni remained independent, and it is likely that Prasutagus was installed as a pro-Roman ruler at this time.

After putting down the rebellion he began expeditions beyond the frontier, beginning with a productive campaign against the Deceangli tribe in north Wales and the Cheshire Gap in 48. This was an astute move as it divided the tribes of North Britain from those in Wales. He was recalled east however after a new rebellion by a faction of the Brigantes. This was quickly suppressed but revealed the dangers in the Romans' client kingdom system of which the Brigantes were a part; troops from the Legio XIV Gemina were stationed in the area to keep the Brigantian peace. At this time the Legio II Augusta held the command in the south east, the Legio IX Hispana was campaigning the north east beyond the Trent, the Legio XX Valeria Victrix held Colchester and the Legio XIV was based at Wroxeter.

Ostorius initiated further Romanisation during his command in the safer southern lands, founding Britain's first colony of military veterans at Camulodunum (modern Colchester) in 49 and probably establishing a municipium at Verulamium (St Albans). His tactical skill rather than his political acumen was his strength however. He had received a difficult brief as the Claudian lowlands were economically unspectacular and Britain's mineral wealth lay in the barbarian lands instead. Capture of these would have to wait until later years.

In the meantime, Caratacus, whose tribe, the Catuvellauni, had been defeated in the first phase of the conquest, had re-emerged as a leader of the Silures of south east Wales. Their rising was controlled by a programme of legionary fortress construction, driving Caratacus north into the lands of the Ordovices. Ostorius managed to force him into an open conflict, after several years of guerrilla war. They fought a battle, probably near the River Severn and possibly near Caersws, where the Romans defeated the British leader in 51.