Gwilym ap Tudur Rhys and Owain Glyndŵr. As a result, the Tudur brothers began planning an attack on Conway Castle. On Good Friday, 1 April 1401, the brothers and 44 men (which included those who had also been excluded from the pardons) infiltrated the castle. They had pretended to be carpenters, and captured the castle while the guard were in church. Negotiations began for the return of the castle on 13 April, with the king represented by Henry "Hotspur" Percy and Gwilym representing the Welsh forces. After seeking a compromise, which would have resulted in pardons being given to the Welshmen, the king
Hywel ab Owain Gwynedd of Anarawd's wedding to Owain's daughter. Owain followed a diplomatic policy of binding other Welsh rulers to Gwynedd through dynastic marriages, and Cadwaladr's border dispute and murder of Anarawd threatened Owain's efforts and credibility. As ruler of Gwynedd, Owain stripped Cadwaladr of his lands, and dispatched Hywel to Ceredigion where he burned Cadwaladr's castle at Aberystwyth. Cadwaladr fled to Ireland and hired a Norse fleet from Dublin, bringing the fleet to Abermenai to compel Owain to reinstate him. Taking advantage of the brotherly strife, and perhaps with the tacit understanding of Cadwaladr, the marcher lords mounted incursions into Wales. Realizing