Remains dating back to Saxon times have been unearthed at a site earmarked for a new railway station.
The existing Castle Station in Northampton will be replaced by a £20m glass and steel building in 2014.
Excavation at the site of the new building has found an ironstone wall, fragments of pottery and a Saxon brooch.
Construction work on the replacement two-storey station is expected to begin in April.
Northampton Castle sat on the current station site in medieval times.
An archaeological study across the full footprint of the new station building is underway.
West Northamptonshire Development Corporation has led the station development plans.
The organisation's regeneration director Chris Garden said: "Not only does Northampton have a bright future; it has a rich and important past.
"The next stage of investigations will help us ensure the history of the site is recorded and respected as the development moves ahead."