Iolo Morganwg is considered by some as having a lasting impact on the Welsh culture
Some will argue as to whether Iolo Morganwg was a fantasist, or a genius and champion for Wales.
But one thing is certain, in 1792, the stonemason from the Vale of Glamorgan presided over the first gathering of the Welsh bardic order, the Gorsedd.
Now, after years of campaigning a plaque in his honour has been unveiled at Primrose Hill in London.
"This will be a real day of celebration for Welsh people everywhere," said the BBC's Huw Edwards.
The broadcaster, who is president of the London Welsh Association, will lead the midday ceremony, which will include a poetic declaration, singing, and of course, the participation of the Gorsedd, in their full bardic regalia.
Permission to have the plaque to Morganwg at the Primrose Hill site had to be granted by the Royal Parks, and is the only such memorial of its kind on the hill.
"We in the London Welsh community are very proud of Iolo Morganwg and his invaluable contribution to the culture of Wales," added news broadcaster Edwards.
"The memorial is long overdue, but we are grateful to the Royal Parks for allowing us to mark Iolo's genius.
"I hope we see a big crowd to give Iolo Morganwg the prominent tribute he deserves."
The plaque has been designed by the sculptor John Meirion Morris, who remarked when commissioned: "It is a privilege to be asked to design such a monument, and to bring a piece of Wales to the very spot that Iolo gathered the first meeting of the Welsh druids."
Actor Matthew Rhys became a member of the modern day Gorsedd in 2008
Born Edward Williams in 1747 in the small parish of Llancarfan, Morganwg was a founder member of the Unitarian movement in Wales, an anti-slavery campaigner, and political radical who called himself "The Bard of Liberty".
His stonemason craft saw him travel widely around Wales and to London, which brought him in to contact with scholarly society.
It was in London that he conjured up the notion of the Gorsedd of the Bards of the Isle of Britain, convincing many of his peers at the time that this was an authentic and ancient institution.
Trappings of his fledgling druidic organisation included the ancient bardic alphabet, a complete invention of Morganwg.
However, regardless of his scholarly deceptions, his creation of the Gorsedd, and the way he associated it with the eisteddfod movement in Wales was the seed that would grow to become today's modern Gorsedd and the National Eisteddfod.
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