What happened during the uprising?
At first Glyn Dwr and his forces were successful in their uprising. They captured Conwy Castle in 1401 and won the Battle of Pilleth in 1402. By 1404 Glyn Dwr had gained control of most of Wales. He pronounced himself the prince of Wales and started to form an independent Welsh Parliament. He also began to make his own plans for foreign policy.
But King Henry’s son, Prince Henry, continued to fight the Welsh rebels and soon won some important battles. By 1408, Prince Henry had captured many of the areas Glyn Dwr had claimed, and won back most of Wales for England.