Frongoch isn’t a big place. But some believe this tiny Welsh village played a significant part in securing Irish independence.

After the failure of the Easter Rising in Dublin in April 1916, Michael Collins and 1,800 other Irish republicans were interned here. Collins took the opportunity to school other prisoners in guerilla warfare, learning the bitter lessons of the mistakes of Easter 1916. As a result, Frongoch was dubbed in Irish ollscoil na réabhlóide, the university of revolution. During the war of independence, the slow-witted British authorities were no match for the revolutionaries.

The Irish at Frongoch played Gaelic football with a Welsh rugby ball on a Frongoch field they called Croke Park after the revered GAA stadium in Dublin. (The ball is now in the care of the National Museum of Ireland.) Tragically, four years later the real Croke Park would be the scene of the massacre of 14 men, women and children by British forces, supposedly prompted by the killing of 14 British intelligence officers at the behest of Michael Collins.

Frongoch’s village Welsh language school, Ysgol Bro Tryweryn, now occupies part of the site of Frongoch prison. A local farmer demolished the last remaining prison hut some years ago not realising its historical significance. But Wales made up for this on the centenary of the Easter Rising in 2016, with commemorative plaques in Welsh, Irish and English, and a ceremony featuring both nations, and the children of Ysgol Bro Tryweryn.

Just outside Frongoch, the Welsh and Irish flags dance in the wind underneath another memorial to the prisoners of 1916. This features men from Galway interned here, and, by a strange coincidence, as I stopped here today a car from Galway pulled into the layby just ahead of me. I chatted briefly to the driver, who said he’d driven past several times but only decided to stop today.

I noticed as we chatted that the flagpole flying the Welsh flag featured a sticker for YesCymru, the campaign for Welsh independence. It seemed appropriate given the history – not just the 1916 connection, but the part this valley played in fuelling Welsh identity and nationalism.

To this day, you will find the words Cofiwch Dryweryn daubed on walls all over Wales: Remember Tryweryn. In the 1960s, a Welsh speaking community just down the road from Frongoch was destroyed to provide water for the English city of Liverpool. All but one Welsh MP voted against drowning Capel Celyn to create a reservoir, but the British Tory government ignored them. English drinkers trumped Welsh villagers. The year after the reservoir opened, Wales elected its first Welsh nationalist (Plaid Cymru) MP, Gwynfor Evans. Sixty years later, Plaid Cymru became Wales’s first pro-independence party to form the Welsh government.

Michael Collins would have raised a toast.