This is a Roman era alley in the City that was discovered during the soon to be completed Bank tube station upgrade project.
Although the deep tunnels that make up Bank tube station were dug out of 50-million year old London clay, far below the archaeology layer, to get down there, a large shaft was dug in Arthur Street – and it passed through layers of human history, uncovering Roman remains.
Although the area was later occupied by medieval buildings, Arthur Street itself only came into existence in 1830 as part of the rebuilding of the area for John Rennie’s London Bridge. Despite that, it was promising to archaeologists as it lay close to the Roman waterfront, not far from the Roman era bridge crossed the Thames, but until you clear away the layers of modern London, you’re never sure what will be found. So next to Monument, on the closed off Arthur Street, at the start of the tube station upgrade, a large shaft was dug down directly in the middle of the road.
And down here, archaeologists from MOLA found a Roman alley that likely ran between two houses linking the Thames to the rest of the City.
Running on either side of the alley were two Roman walls that ran north-south, and painted plaster fragments from the walls. To the area south of Arthur Street were a series of artificial terraces constructed by the Romans for masonry warehouses and domestic or commercial buildings, leading down to what was likely Roman London’s first major riverside quay.
During the excavation, archaeologists concluded that the first buildings and initial use of the alley between them can be provisionally dated to around AD 70-100/120.
Excavating the alley surface, which had been initially lined with a floor of gravel, brickearth and compacted mortar fragments, they found fragments of wall plaster decorated with a rare bright blue pigment as well as a rare and expensive cinnabar pigment that could only have come from Spain, showing how important international trade was to London even then. The MOLA archaeologists suspect that the decorated mortar would have come from a high-status building nearby that had been demolished.
The alley, leading down to the river was apparently heavily used and to have been regularly resurfaced, and at one point widened, and it received a major resurfacing in around AD180-250. The research suggests that the alley would likely have sustained heavy traffic to and from the quayside to the south.
Two buildings on either side flanked the alley, of which the western side wall is the best preserved, and they uncovered just over 5 metres of Roman wall during the excavations. They also found a small horde of 23 Roman coins in the western building dating to around AD 348.
The eastern building seemed to have had its original wall cut down and rebuilt a bit futher to the east – indicating the time that the alley was widened, and there’s some evidence found that the occupants may have been metal workers, either with a smithy in the building or nearby.
Although possibly still in use, the last archaeological evidence for Roman activity in the alley dates to the 3rd-century, after which they start to come into medieval remains, on top of the now buried alley.
MOLA’s assessment of the findings concluded that the remains at the Arthur Street site are sufficiently important and substantial that their publication will be required by the Corporation of London curator.
Over the next few months, the shaft dug down by Dragados, who carried out the Bank tube station upgrade will be filled back in with a soft concrete, and while the Roman remains had to be removed to make space for the construction shaft, there may be more of this old Roman alley under the streets of London to be uncovered in the future.
The post-excavation assessment was published by MOLA in March 2018, covering the Bank upgrade project work sites at Arthur Street (ART15) and 12–14 Nicholas Lane (NOS17).