Today marks the 621st anniversary of that fateful day in 1400 when Owain Glyndŵr raised his banner and staked his claim to be Wales’ Mab Darogan – leader of destiny. Any new national holidays should include September 16 as Glyndŵr Day.

A few years ago, at the annual Glyndŵr lecture at Galeri Caernarfon, I spoke on 'Owain Glyndŵr, Wales and Europe'. It generated much interest, though Wales’ subsequent Brexit vote – for which we now pay the price – has put a temporary damper on that aspect of Glyndŵr’s legacy.

Nonetheless, Glyndŵr’s message has a growing contemporary relevance for Wales today, as the Johnson government systematically sets about reversing the national progress which Wales has made over recent decades.

It was as a protest against the way Wales had been treated by a succession of English monarchs and their henchmen, following the barbarous slaughter of Llywelyn at Cilmeri in 1282, that Owain Glyndŵr made his stand for the Welsh people: a heartfelt protest – but so much more.

READ MORE: St David's bank holiday? TUC calls for four more holidays

We Welsh are good at protests but they often result in a tan siafins, a fleeting stand, whose slogans become little more than a memorial to the tyranny that had inspired them.

Having made their point, protesters have so often compromised with their oppressors, finding a modus vivendi – and reverting to business-as-usual. The English monarch, and later the Westminster system, were so clever at buying off meaningful rebellion.

But Owain Glyndŵr had more than a box of matches; he had a political programme. That is the first prerequisite for any modern-day leader who, like Glyndŵr, wants to build not just a power base but a modern state to serve the Welsh nation; a dream to engage people in every part of Wales as partners.

Secondly, Glyndŵr knew that a small nation like Wales couldn’t live in isolation; he forged alliances with European leaders, creating – for a time – a credible modern state in a European setting.

Thirdly, Glyndŵr, in his tripartite agreement, appreciated the relevance of dividing England; a lesson which Wales – and Scotland – still haven’t applied in our contemporary politics.

Fourthly, Glyndŵr recognised the spiritual, as well as material, dimensions of the Welsh nation. His vision for Wales’ church, its place in Christendom and for two universities, laid down values which, over subsequent centuries, triggered the imagination of the Welsh people and inspired its culture.

READ MORE: Wales needs to break down barriers when engaging with government

Fifthly, Glyndŵr was never captured, reflecting the huge loyalty he had inspired amongst his followers. He possibly lived his remaining years with daughter Alice Scudamore in Herefordshire, though other theories abound.

Welsh people were enthralled by the suggestion that Y Mab Darogan was still alive and yearned for his nation to be free. That dream persisted because people wished it so to be; and resolved that it will, one day, be reality.

So Glyndŵr Day, September 16, should be a national holiday. Let’s resolve that next year we rekindle the flame and that by the 625th anniversary, it will be a torch for independence – for which Glyndŵr worked and to which an ever-growing proportion of our nation aspires.

If you value The National's journalism, help grow our team of reporters by becoming a subscriber.