Adrian Dunbar has admitted he was left exhausted by the battle scenes on BBC Two drama The Hollow Crown.
The Irish actor plays Richard Plantaganet - who defeated the Lancastrian forces at St Albans in 1455 - in the adaptations of Shakespeare's history plays.
He told the Radio Times: "You've got the armour and everything on, and you think, 'This is going to be great.' Then they give you a sword, and you think, 'Ah, it's not too bad.' And after ten minutes you're thinking, 'Please, I can't be doing this all day.'
"I mean, I really don't know how people sustained themselves in real battles. Someone would just come along and slaughter you because you'd be too tired to lift a sword."
The Line Of Duty star believes the series is well-timed.
"It's got everything - battles, power being wrested from people, witchcraft - it's the proper Game Of Thrones," he said.
"I think there are a lot of young people, in particular, who watch Game Of Thrones, so these plays won't be as alien to them now as they might have been to audiences watching 30 or 40 years ago."
This week's Radio Times is on sale from Tuesday.