The remains of several Roman buildings and streets have been uncovered in Brough.
Ground penetrating radar was used on the Burrs Playing Field, to reveal the site's Roman history.
As a part of the 'Petuaria ReVisited' project, it's believed a Roman theatre could have been in the field.
Dr Peter Halkon from the University of Hull, who was the Lead Archaeologist on the project, says the discovery rewrites the town's history.
He says: "To have such a building shows Brough must have been of some considerable importance. What this new research has shown, it has really revolutionised our ideas of what's going on and added a new chapter to our knowledge of Roman Britain."