The city was founded in 71 AD, when the Ninth Legion conquered the Brigantes and constructed a wooden military fortress on flat ground above the River Ouse close to its confluence with the River Foss.

The fortress, whose walls were rebuilt in stone by the VI legion based there subsequent to the IX legion, covered an area of 50 acres (20 ha) and was inhabited by 6,000 legionary soldiers.

In 314 AD a bishop from York attended the Council at Arles to represent Christians from the province.

While the Roman colonia and fortress were located on high ground, by 400 AD the town was victim to occasional flooding from the Rivers Ouse and Foss and the population reduced.

By the time of the Roman conquest of Britain, the area was occupied by a tribe known to the Romans as the Brigantes.

The Brigantian tribal area initially became a Roman client state, but later its leaders became more hostile and the Roman Ninth Legion was sent north of the Humber into Brigantian territory.

The last ruler of an independent Jórvík, Eric Bloodaxe, was driven from the city in 954 AD by King Eadred in his successful attempt to complete the unification of England.

In 1068, two years after the Norman conquest of England, the people of York rebelled.

Alternatively, the word eofor already existed as an Old English word for wild swine, which is a cognate of the current Low Saxon word eaver and Dutch ever.

The Anglo-Saxon newcomers probably interpreted the ebor part as eofor, and -rac as ric (meaning rich), while -um was (and is) a common abbreviation of the Saxon -heem, meaning home. As is common in Saxon place names, the -um part gradually faded; eoforic.

The first mention of York by this name is dated to circa 95–104 AD as an address on a wooden stylus tablet from the Roman fortress of Vindolanda in Northumberland.