Owain Glyndwr Day

AmeriCymru has this bit of Welsh history:

Today is Owain Glyndwr Day, and the anniversary of the proclamation of Glyndwr as Prince of Wales.
The revolt of Owain Glyndŵr began as a local dispute with his powerful neighbor, Sir Reginald de Grey, during 1399 and 1400.  The cause of this dispute was a piece of common land that Glyndŵr asserted had been stolen by Grey, and he appealed to the new king, Henry IV, for justice. None was offered and, after repeated appeals, all ignored, Glyndŵr raised his standard outside Ruthin on 16 September 1400, effectively proclaiming himself Prince of Wales.  To the men of Wales who followed him, however, Owain Glyndŵr was the symbolic leader of a resistance movement that turned into a widespread national uprising. Glyndŵr wasn't the only one with grievances against acquisitive and arrogant Marcher lords like Grey; many Welshman had long harbored a similar sense of frustration at unjust and oppressive English rule. Such men flocked in droves to Owain's banner and, by 1401, the revolt had spread like wildfire the length and breadth of Wales.
Owain Glyndŵr was a Welsh landowner, and a direct descendent of the dynasties of Powys Fadog (through Madog ap Maredudd, his great, great, great, great grandfather) and Deheubarth (through his maternal grandfather) and indirect descendant of the Gwynedd dynasty (through his connection with Owain Gwynedd and Gruffudd ap Cynan). Owain owned a manor in Sycharth and owned lands in the lordship of Glyndyfrdwy, a part of the commote of Cynllaith, and lands in Cardiganshire.  The Glyndŵr rebellion began in 1400, following years of increasing resentment among the Welsh people at the English treatment of them. The rebellion marked a change in  Wales, as the aristocratic families of Wales, who came to be Glyndŵr’s main supporters, were traditional supporters of the Crown.  The Glyndŵr rebellion began with an attack on the town of Ruthin in 1400, followed by attacks on Rhuddlan, Flint, Holt, Oswestry, and Welshpool. The revolt was supported by  the Welsh people  and many Welsh people in exile returned to join the revolt.  In 1404, Glyndŵr held a Parliament in Machynlleth and signed agreements with Scotland and France. In 1406, Owain Glyndŵr sent a letter to King Charles VI of France, asking for his support to the rebellion and outlining his visions for Welsh independence, establishing an independent church in Wales, and establishing two Welsh universities.
The Welsh poets professed that Glyndŵr was in fact the prodigal son, who had been sent to free the Welsh people from the English crown, and Glyndŵr was also immortalized by William Shakespeare, in his play, Henry IV: Part 1.  Owain Glyndŵr certainly had a tenacious personality and excellent leadership skills: he was never betrayed by his army, and his rebellion went on for more than a decade. He succeeded in overcoming the English army several time, taking Harlech and Cricieth castles in the process, but in 1409, he was cornered in Harlech Castle, bringing an end to his rebellion. Owain somehow managed to escape, but paid a heavy price for his political ambitions: his wife, two daughters, and grandson were captured and imprisoned in London until their deaths. Owain Glyndŵr refused the offer of a pardon by the Crown, and it appears that Owain himself died in 1416, in his daughter Alis’ home.
Owain Glyndŵr’s Day is now celebrated annually on 16 September.

Rico says he's proud of his Welsh ancestry (through his paternal grandmother, a Jones).