Londinium: Rome at the Edge of the World
The Romans did not found London because they needed a city there. They founded it because they needed a crossing point on the Thames, and the crossing point became a city because trade and administration followed the military logic that had chosen the site. The settlement that grew up at the first substantial tidal ford on the Thames — approximately where London Bridge stands today — was called Londinium, and within a century of its founding it had become the administrative capital of the Roman province of Britannia and one of the most important commercial cities in the northwestern empire. Britain was at the edge of the known world; Londinium was a world city transplanted to the edge.
The founding is conventionally dated to shortly after the Claudian invasion of 43 AD, when Roman forces established a bridgehead across the Thames and began organizing the supply and administrative infrastructure for the conquest of the island. The earliest archaeological evidence for substantial settlement dates to the 50s AD, and the first Londinium was not a military base — the legionary fortresses were elsewhere — but a civilian settlement organized around the bridge crossing and the commercial activity it generated. The river was the city’s reason for existing: upstream enough to be above the tidal limit, downstream enough to allow seagoing vessels to reach the docks, at the lowest practical crossing point of the Thames.
The Boudican revolt of 60 or 61 AD burned the city to the ground. Boudica, queen of the Iceni tribe, led a coalition of tribes against Roman rule in response to the mistreatment of her family following her husband’s death and the violation of the treaty arrangements he had made with Rome. The revolt destroyed three Roman cities — Camulodunum (Colchester), Londinium, and Verulamium (St. Albans) — with such completeness that the destruction layer is archaeologically visible across all three sites as a distinct horizon of burned material. The Roman governor Suetonius Paulinus, caught between his campaign in Wales and the revolt behind him, evacuated Londinium rather than defend it with insufficient forces. The archaeological layer of burned daub and red ash that marks the revolt is among the clearest datable events visible in London’s underground stratigraphy.
The city rebuilt rapidly and on a grander scale. The second Londinium of the late first and second centuries was a substantial Roman city: a forum and basilica complex — the largest north of the Alps — containing markets, law courts, and administrative offices; a governor’s palace near the riverfront; an amphitheater beneath what is now the Guildhall; public baths, temples, and warehouses. The city walls, built in the early third century from Kentish ragstone shipped up the Thames, enclosed an area of approximately 130 hectares — the same area enclosed by the medieval city that would much later stand within them. The walls remained the defining boundary of the city for nearly a thousand years after the Roman withdrawal.
The population at its peak — probably the late second century — is estimated at between 30,000 and 60,000 people, making Londinium one of the largest cities in the northwestern provinces but modest by Mediterranean standards. The population was thoroughly mixed: inscriptions record people from Gaul, Germany, Greece, the eastern Mediterranean, and North Africa living and working in the city. A funerary inscription for a woman named Regina, a freed slave and wife of a merchant named Barates from Palmyra in Syria, buried near the Hadrian’s Wall garrison town of South Shields but typical of the kind of person who moved through the commercial network Londinium anchored, suggests the reach of the connections the city participated in.
The Roman withdrawal from Britain in the early fifth century — conventional date 410 AD, when the Emperor Honorius reportedly told the cities of Britain to look to their own defense — left Londinium in a state whose archaeological interpretation has been extensively debated. The city did not immediately collapse, but the population declined sharply, the administrative infrastructure dissolved, and the sophisticated commercial economy that had sustained urban life contracted. The roads continued to be used. The walls continued to stand. The bridge may have remained functional for a generation or more. But the city as a Roman urban organism — with its forum, its baths, its regular magistrates and their records, its commercial networks tied to the Mediterranean system — ended. The settlement that slowly developed within the Roman walls across the fifth and sixth centuries was something different.
What London inherited from Londinium was essentially geological: the site, the river crossing, and the walls. The specific Roman institutions, the Latin language, the administrative forms — these did not survive in continuous tradition in Britain the way they survived in Gaul or Spain or Italy, where the Roman population remained and the church maintained Latin as a working language. Britain was more thoroughly de-Romanized after the withdrawal than any comparable province, which is one of the reasons English law and culture diverge more substantially from Roman legal and cultural traditions than their continental European equivalents. London is built on Roman foundations, literally — the archaeology of the City of London is Roman archaeology beneath medieval archaeology beneath early modern archaeology beneath the modern city. It owes its existence to a Roman military and commercial decision made two thousand years ago. Almost nothing else of Londinium survived the withdrawal intact.