The first Roman invasion took place across the River Dee.

It was aimed at dividing the people of the highlands of Wales from the highlands of the north of what would later become England.

The campaign of AD 48 brought about the submission of the Deceangli in North Wales. In the following year, the Romans sought to divide the people of Wales from those of south western Britain by establishing major fortresses at Gloucester and Usk. They realised that to conquer Britain they had to cut off the various tribes from each other and deal with them individually.

The Roman advance was hindered by the resistance of the Silurians in South East Wales, under the leadership of Caratacus (Caradog), a prince of the Catuvellauni of Essex exiled by the Romans.

Caratacus moved north to fight the Romans in Anglesey and Caernarfon. He was defeated and his family were captured, though Caratacus himself fled to the Brigantes.

The Brigantes queen, Cartamandua, betrayed him to the Romans. He was taken in chains to Rome, where he asked, "Why do you, with all these grand possessions, still covet our poor huts?" He died in Rome in 54 AD.

Six years later the Romans attacked Anglesey, the stronghold of the druids, the inspirers of British resistance. According to the historian Tacitus, the legionnaires took off their clothes and swam across the Menai Straights to battle the druids.

By 75 the Silurians had been conquered and, by the AD 60s, with the defeat of the Ordovices, the whole of what would be England and Wales had come under Roman control.