 When Scrope brought an action, Grosvenor maintained his family had worn these arms since his ancestor had come to England with William the Conqueror in 1066.The case was brought before the Court of Chivalry and presided over by Thomas of Woodstock, 1st Duke of Gloucester, the Constable of England.Several hundred witnesses were heard and these included John of Gaunt, Duke of Lancaster, Geoffrey Chaucer, himself a close friend of John's; and a then little-known Welshman called Owain Glyndŵr, who gave his evidence with others at the Church of St John the Baptist in Chester on 3 September 1386.