Saxon London of the seventh to ninth centuries - located in an area approximate to today's West End and known as Lundenwic - was a well laid- out town, with well-maintained streets, a money economy and a probable population of around 10,000.
Archaeologists have found the remains of a grid system of roads - including several minor ones running east-west and one of the town's main drain- flanked five-metre wide north-south thoroughfares, which had been resurfaced at least 10 times in 200 years.
Excavations also yielded 20 Roman coins - which suggest their bronze money was being reused as a low-value currency in the seventh- to ninth- century. Saxon coins would have been fine for middle-to-high value purchases but, being silver, were of too high denomination for everyday purchases.
But the most important information discovered by the team from the Museum of London Archaeology Service was the housing density. Relatively high, it suggests that Lundenwic may well have had a population of something between 8,000 and 12,000.
London was founded by the Romans in the first century. By the early second century it had a population of 45,000, which fell back to around 15,000 by AD300.
The fifth- to sixth-century size and population of London - if it existed at all in those two centuries - is a complete mystery. But the current research does show that at a fresh site - that of the present West End - in the seventh and eighth centuries, a new London, replete with metal, textile and bone industries, flourished and only shrank when the city was re-established within the old Roman walls (the modern City) in the ninth century.
The finds from the excavations at Covent Garden are on display at an exhibition - "Saxons at the Opera" - at the Museum of London in the City until 15 February.