He opposed Richard II, and a year after Bolingbrooke usurped the throne, he began his fight for independence, actually calling his own parliament in 1405.  
His rebellion had begun as a simple land feud with one of his neighbors, Reynold, Lord Grey of Ruthin.  Though his time was short, one of his descendants, at the end of the Wars of the Roses, took the English throne as Henry VII.  He opposed Richard II, and a year after Bolingbrooke usurped the throne, he began his fight for independence, actually calling his own parliament in 1405.  FTP, name this nobleman who unsuccessfully fought for autonomy for his native Wales and appears as a prominent character in Shakespeare's Henry IV, Parts 1 and 2.
His rebellion had begun as a simple land feud with one of his neighbors, Reynold, Lord Grey of Ruthin.  
Owen Glendower or Owain Glyndwr or Owain ap Gruffudd