 Grosmont 's uncle , Thomas of Lancaster , was the son and heir of Edward I 's brother Edmund <unk> . Through his inheritance and a fortunate marriage , Thomas became the wealthiest peer in England , but constant quarrels with King Edward II led to his execution in <unk> . Having no heir , Thomas 's possessions and titles went to his younger brother Henry – Grosmont 's father . Earl Henry of Lancaster <unk> to the deposition of Edward II in <unk> , but did not long stay in favour with the regency of Queen Isabella and Roger Mortimer . When Edward III took personal control of the government in 1330 , relations with the Crown improved , but by this time the older Henry was already struggling with poor health and blindness . 
