The first attack on the Celtic tribes of what is now Wales was made under the legate Publius Ostorius Scapula about 48 AD. Ostorius first attacked the Deceangli in the north-east, who appear to have surrendered with little resistance. He then spent several years campaigning against the Silures and the Ordovices. Their resistance was led by Caratacus, who had fled what is now southeast England when it was conquered by the Romans. He first led the Silures, then moved to the territory of the Ordovices, where he was defeated by Ostorius in 51 AD. Caratacus fled to the Brigantes, whose queen handed him over to the Romans.
The Silures were not subdued, however, and waged effective guerrilla warfare against the Roman forces. Ostorius died with this tribe still unconquered; after his death they won a victory over the Roman Second Augusta Legion, Legio II Augusta. There were no further attempts to extend Roman control in Wales until the governorship of Caius Suetonius Paulinus, who attacked further north and captured the island of Anglesey in 60 or 61 AD. However he was forced to abandon the offensive to meet the threat from the rebellion of Boadicea. The Silures were eventually subdued by Sextus Julius Frontinus in a series of campaigns ending about 78 AD. His successor Gnaeus Julius Agricola subdued the Ordovices and recaptured Anglesey by the beginning of 79 AD.
The Romans occupied the whole of the area now known as Wales, where they built Roman roads and Roman forts, mined gold and conducted commerce, but their interest in the area was limited because of the difficult geography and shortage of flat agricultural land. Most of the Roman remains in Wales are military in nature. The area was controlled by Roman legionary bases at Deva Victrix (modern Chester) and Isca Augusta (Caerleon), with roads linking these bases to Roman auxiliary forts such as Segontium (Caernarfon) and Moridunum (Carmarthen). Romans are only known to have founded one town in Wales, Venta Silurum (Caerwent) in (Monmouthshire), although the fort at Moridunum (Carmarthen) was later superseded by a civilian settlement. The modern-day Wales is thought to have been part of the Roman province of Britannia Superior and later of the province of Britannia Prima, which also included what is now the West Country of England.