Welsh people should be asked whether they want to take the Prince of Wales title back when it next becomes vacant, believes Michael Sheen.
The actor said the title, currently held by Prince William, "symbolises something that was essentially a put-down to Wales".
"Obviously that was a long, long time ago, but these things have power still," he added.
The Hollywood actor was speaking ahead of his forthcoming portrayal of Owain Glyndŵr, the last Welsh-born Prince of Wales, in a new theatre production at the Wales Millennium Centre in Cardiff.
Kensington Palace declined to comment.
The Royal Family reserves the Prince of Wales title for the heir apparent to the British throne, in a centuries-old tradition.
William and his wife Catherine, the current Princess of Wales, were given the titles by King Charles III following the death of Queen Elizabeth in 2022.
The Prince of Wales title is granted at the discretion of the monarch, as opposed to passing down automatically, but it is rooted in a bloody history.
Llywelyn ap Gruffydd was the last prince of an independent Wales before it was conquered by the English.
In 1282, Llywelyn was killed in battle and his head sent to King Edward I, before being displayed at the Tower of London.
Edward I then invested his son Edward II as the Prince of Wales in 1301.
A hundred years later, Owain Glyndŵr instigated a 15-year revolt against the rule of King Henry IV and claimed the title Prince of Wales, before Wales was reconquered by the English.
Glyndŵr has since become a figurehead for Welsh nationalism and there are statues, monuments, pubs and street names across Wales commemorating him.
Sheen, who will portray Glyndŵr in Owain & Henry this November, said the production had made him think more about the history of Wales, and he hoped it would "start a conversation" - including questions about why the Prince of Wales does not come from Wales.
He said the title "symbolises something that was essentially a kind of put-down to Wales", saying that when Edward I made his son the Prince of Wales, it was an attempt to keep Wales "in your place".
Sheen believes the people of Wales should be asked what happens to the title when it next becomes vacant.
He added: "The Welsh people might decide that they don't want the title Prince of Wales to come back to Wales, and they're happy with it the way it is.
"But I think it would be nice to be asked."
In 2017, Sheen handed back his OBE for services to drama after learning more about the history of his native Wales.
Owain & Henry is a co-production between Welsh National Theatre, of which Sheen is artistic director, and the Wales Millennium Centre.
Linus Roache will portray Henry IV, while Sheen will co-direct the play alongside Steffan Donnelly.
Sheen said learning more about Welsh history had changed his understanding of his own national identity.
"It's enriched and nourished my life and my sense of my national identity so much to find out more and more about this," he said.
"And so I think if this production can be a catalyst for a lot of people being able to engage in that, I think that would be fantastic."
Sheen said much of the history he remembered being taught at school had been "from an English point of view" and there was "a massive hole in my knowledge about my own country", which he believed was the case for a lot of Welsh people.
The new play also stars Rakie Ayola as Owain's pragmatic wife Mared.
Ayola last acted opposite Sheen 40 years ago when they were both teenagers, as part of a National Youth Theatre of Wales residency.
She said: "[Michael and I] have got some unfinished business, which is perfect to play these two married people, who've got a lot going on."
The Holby City actor, who grew up in Ely, Cardiff, said Owain Glyndŵr was only known to her as the name of a pub in the city centre until she was an adult, despite him being "an integral part of Welsh history".
Welsh history is now a compulsory part of the Curriculum for Wales.
Graeme Farrow, creative director at the Wales Millennium Centre, said: "I think producing ambitious theatre on this scale is even more of a gamble than ever because the costs have up, the financial risks are greater than ever, but with this we knew the risk was worth taking, it's a brilliant play.
The response has been sensational. It's going to be pretty much full every night if not sold out for the whole of its run which is a huge relief, but now it's all about putting on the show."
Owain & Henry runs at the Wales Millennium Centre from 5 November until 28 November.
