More than 1,500 are estimated to have flooded into Huntingdon town centre for the first events in Huntingdonshire’s History Festival.
They saw members of the Sealed Knot recreate the occupation of the town by parliamentary soldiers.
Geoffrey Stalker, one of the organisers, said: “It was a fantastic day. It was lovely to see so many people there.”
Colonel John Pickering, His regiment of Foote, got the festival under way with activities in the market square where they gathered around a cannon.
They also set up a living history encampment in the grounds of All Saints Church where members produced food from the period.
Youngsters were given the chance to learn how to drill with a pike and there was also a mock trial in the town hall’s period courtroom - which was packed with spectators.
The town hall also saw the work of a lacemaker and an alchemist and the church, library and Cromwell Museum were all involved.
Huntingdon MP Jonathan Djanogly and deputy mayor, Councillor Steve McAdam, opened the festival, which runs throughout July.