Chester races packs them in: 250,000 people over the 15-event racing season that runs from May to September. But most race-day revellers probably remain unaware that Chester racecourse is the oldest in Britain.

"Stand here," says race-day guide Chris Clayton, resplendent in his pale-blue gilet as we approach gate nine. We're overlooking the course from the medieval city walls. "This is my favourite view," he says. "For a cross-section of history from Roman times to the modern day, it's all alive here." The gate is now the main entrance to the Dee enclosure but it overlooks the old Roman port, built on the banks of the river Dee, which intersects the city.

The Romans established Chester as a safe anchorage point for access to the Irish Sea and it remained a busy trading port through the medieval period until the build-up of silt left the land, known as the Roodee, as a public space.

Chris leads us on, taking the steps down the side of Restaurant 1539 to the Tattersalls stand with views over the narrow home straight. The restaurant's name references the first recorded race at the Roodee, on 9 February 1539. Horse racing was introduced, initially, to replace the annual Shrove Tuesday football match, banned in 1533 for being too violent. "Chester's then lord mayor, Henry Gee, gave his consent," says Chris. "Which is why we still talk about going to the gee-gees."

• What to see: Chester Racecourse (01244 304610, chester-races.co.uk)