Deep beneath a modern office building in London, archaeologists have made an extraordinary discovery – the remains of the first Roman basilica in the city.

Constructed shortly after the Roman conquest of Britain, this impressive structure was a key part of Londinium’s bustling forum.

A section of wall from the Roman basilica. Image: ©MOLA.

The basilica, comparable in size to a football field, dominated the city’s landscape. Its scale served as a powerful symbol of Roman authority, showcasing their control over social, commercial, and political life. 

“This is one of the most significant discoveries made in the city in recent years,” said Sophie Jackson, MOLA director of development.

The existence of a 2,000-year-old Roman basilica in the area near Leadenhall Market was already suspected, but the exceptional state of preservation astonished the archaeological team.

“The levels of preservation of the basilica have far exceeded our expectations, and we have possibly the most important part of the building,” said Jackson. 

A reconstruction drawing of the first London Forum. Image: ©Peter Marsden.

The Roman Tribunal: Where London’s history was made

After digging test pits into the ground around the estimated location of walls and foundations, the researchers discovered that their calculations yielded “extraordinary” results: massive foundations and walls made of flint, ragstone, and Roman tiles. 

Research and previous excavations had suggested that the building might have stood at the northern end of the first Roman basilica. However, they were “unprepared” for the scale and significance of their find.

Some of the unearthed structures measured up to 32 feet long (almost 10 metres), indicating they were part of the Tribunal. This raised platform was where prominent Roman officials conducted official business and shaped the course of London’s history.

“It’s the place you came to do business, to get your court case sorted out, it’s where laws were made, and it’s where decisions were made about London, but also about the rest of the country,” Jackson told the BBC.

The two-storey basilica overlooked bustling markets, vibrant festivals, and important public gatherings. However, despite its imposing presence, it was soon deemed insufficient for the growing Roman settlement. Within two decades, it was replaced by an even grander forum.

A renovation project that will incorporate ruins

The remarkable discovery was made during an archaeological investigation commissioned by Hertshten Properties, which plans to redevelop its commercial building at 85 Gracechurch Street. MOLA was tasked with ensuring no historically significant remains were disturbed during construction. 

Recognising the value of the find, Hertshten Properties now aims to incorporate the Roman ruins into its renovation plans. In collaboration with MOLA and the London Museum, it envisions a new public exhibition space that will offer visitors an immersive experience of Roman London.

“To actually see people using and enjoying the space, moving through the public hall and down to see the remains, will be absolutely incredible,” James Taylor, of architecture firm Woods Bagot, told the BBC. 

Pending approval of the new plans, further excavations will continue in the spring of 2025. The site should hold more secrets from a pivotal period in London’s history.