In summary, the battle was contested by a flying column led by Prince Rupert that left the besieged City of Oxford late on 17th June 1643 and an informal collection of parliamentarian cavalry, billeted in and around Thame, and hastily assembled early on the morning of 18th June in response to news of Rupert’s raid that was still in progress.
The main engagement began when Prince Rupert, whilst in the process of escorting prisoners and looted livestock back into Royalist Oxford, chose to turn and fight his parliamentarian pursuers in a corn field not far from the village of Chalgrove. During this relatively brief engagement the royalists routed their disorganised pursuers. The parliamentarian survivors fled. Hampden was wounded at an early stage in this action. He rode off the battlefield to Thame where he died six days later.
The details of the events of 17th – 18th June 1643 remain disputed. The latest published research suggests that historians may have misunderstood the nature and importance of the battle, the number of combatants involved and even the location where Hampden received his mortal wounds. Gill and Derek Lester have set out a radical reassessment of the battle in their article reported in the Oxoniensia journal 2015.