The Welsh Rebellion was a war fought from 1300 to 1305, lead by the Duke of Powys Henry Flint (later Arwyn Flint) against Edward I of England. It was a direct result of the Edwardian Conquest of Wales, which had ended in 1289.
1289 - 1300: Origins
The Welsh Rebellion has its origins in a series of uprisings against English rule, the first one beginning on the evening of 4th February, 1291 in Carmarthen. They quickly became troublesome for King Edward, and he granted thirty-two year old Welshman Henry Flint the Duchy of Powys in 1293 in order to keep control over Wales and calm the people down by placing someone of their own culture in control of them. Henry quickly put out the spark of multiple rebellions, with the last and smallest one ending in 1295. Henry, however, united many smaller factions opposed to English rule under his own, which he had formed in 1296. It quickly swept across the lords and ladies of Wales, and by 1299 it encompassed half of Wales. Edward found out about the faction in the later half of 1299, however, and attempted to revoke Henry's title. Henry refused to give it up, and started the Welsh Rebellion earlier than he had planned on February 27th, 1300.
1300: The Battles of Montgomery
Shortly after Henry Flint had mobilised his troops, an English army arrived in Montgomery, Powys from Chester and began to lay siege to it. Henry lead a suicidal clash with them the day they arrived, and inflicted significant losses to the English. The battle was ill-fated for the Welsh, however, as Henry was injured during the battle and by the end of it they were left with only twenty-nine survivors, who had to flee to Gwynedd. There, Henry conscripted soldiers in the masses, and two months later he lead a strategic march into Powys to fight back the English forces. After a night of preparation for the Welsh and one of drinking and singing for the English, the battle began in the early hours of the morning. The Welsh suffered significant losses, but wiped out the drunken English army. After this victory, the Duke of Dyfed entered the independence war.
1303: The Formation of the Kingdom of Wales
After a small chain of victories against the English lasting from 1300 - 1302, Henry was pressured by his council to proclaim himself the King of Wales. He initially only fought to free the Welsh from the English, but decided he would ultimately become the nation's king as he had a claim to its throne and the people, his vassals, and the dukes working in partnership with him looked up to him. He formed the Kingdom of Wales on July 1st, 1303 and celebrated with a party in Camarthen Castle, which a significant portion of his armies and lords attended. During the early morning of July 2nd, the castle was stormed by English troops, who had been alerted by Henry's traitorous Chancellor, Donald Cecil, there would be a party in the castle and the rebellion could be quashed there. The drunken Welsh soldiers and lords fought back against the English, but were easily wiped out in a matter of minutes according to Cecil's journal. Henry was captured at the end of the fighting and was beheaded outside of the castle with a war axe, and his body was tossed into the River Twyi. His wife, Gwendolyn, was captured and raped by the English soldiers after being forced to watch her husband's beheading, before she was flayed alive and also tossed into the river.
Their seventeen year old son, Arwyn Flint, immediately inherited the Kingdom of Wales and was asked to surrender by Edward I. He refused, and organised a marriage with Princess Reine of France - the daughter of the French King. He called the French into the war after the marriage ceremony had taken place in November 1303, and by February 1304, the Welsh Rebellion was backed by the French and was stronger than ever.
1304: The End of the War
The Welsh-French forces first clashed with the English in April 1304, with the aim to take back the Duchy of Dyfed. The battles and sieges lasted until October 1304, but ended in victories against the English. A push to take Glamorgan and lay siege to English towns and castles began in December 1304. The objective to take Glamorgan was completed by May 1305, but Edward I would not surrender. The Welsh and French combined forces pushed in from the West, while French armies landed in the South and sieged the countryside. The Welsh Rebellion ended in November 1305, after Edward I was captured by the Welsh and French during the Siege of Westminster and was executed at the hands of King Arwyn Flint. Edward's son, Edward II of England, admitted surrender, and it became once of the greatest moments in Welsh history.