The rousing tune of ‘Men of Harlech’ is Wales’s alternative national anthem, much loved by rugby fans and regimental bands alike. According to the movie ‘Zulu’ it was even belted out by the garrison at Rorke’s Drift.

No wonder Castell Harlech was the inspiration for this tale of heroism in the face of overwhelming odds. Its great towers and rugged walls saw one siege after another during some of the most epic encounters of Welsh history.

During the Wars of the Roses the Lancastrian-held castle was surrounded by an immense Yorkist army commanded by William Herbert of Raglan. Poet Hywel Dafi told of men being ‘shattered by the sound of guns’ with ‘seven thousand men shooting in every port, their bows made from every yew tree’.

Under this furious onslaught the castle succumbed in less than a month. Fifty prisoners were taken including the Welsh constable Dafydd ab Ieuan ab Einion, who had kept ‘little Harlech for so long, alone faithful to the weak crown’.

These were the heroic ‘Men of Harlech’ of the song. Unless, that is, you believe the alternative theory.

In 1404 the castle fell to the charismatic prince Owain Glyndŵr during the last major rebellion against English rule. Together with nearby Machynlleth it became the centre of Glyndŵr’s inspiring vision of an independent Wales.

He moved his main residence and court here and summoned his followers from all over the country to attend a great parliament. It may well have been at Castell Harlech that he was formally crowned Prince of Wales in the presence of envoys from Scotland, France and Spain.

But this glory didn’t last. By 1409 Harlech was besieged by the forces of Harry of Monmouth – later Henry V, hero of Agincourt. One huge cannon nicknamed ‘the king’s daughter’ actually burst during the relentless bombardment he rained down on the castle walls.

Eventually, hungry and exhausted, the garrison fell. Glyndŵr himself escaped although his wife and daughters were captured. Might these gallant Welsh defenders be the true Men of Harlech?

There was still time for one more famous siege. From the spring of 1644 Harlech was defended for the king by its constable Colonel William Owen. It was the very last royalist stronghold to fall. By the time its surviving garrison of 16 officers, gentlemen and invalids finally surrendered in 1647, it marked the end of the English Civil War.