 Lancaster was married to Isabella , daughter of Henry , Lord Beaumont , in 1330 . The two had no sons , but two daughters : Maud and Blanche . While Maud was married to William I , Duke of Bavaria , Blanche married Edward III 's son John of Gaunt . Gaunt ended up inheriting Lancaster 's possessions and ducal title , but it was not until 1377 , when the dying King Edward III was largely incapacitated , that he was able to restore the palatinate rights for the county of Lancaster . When Gaunt 's son Henry of Bolingbroke usurped the crown in 1399 and became Henry IV , the vast Lancaster inheritance , including the Lordship of Bowland , was merged with the crown as the Duchy of Lancaster . 
 Lancaster was married to Isabella , daughter of Henry , Lord Beaumont , in 1330 . The two had no sons , but two daughters : Maud and Blanche . While Maud was married to William I , Duke of Bavaria , Blanche married Edward III <a href='null_genetive' title='1'><mark>'s</mark></a>son John of Gaunt . Gaunt ended up inheriting Lancaster <a href='null_genetive' title='2'><mark>'s</mark></a>possessions and ducal title , but it <a href='negative_concord' title='3'><mark>was</mark></a> <a href='negative_concord' title='4'><mark>not</mark></a>until 1377 , when the dying King Edward III was largely incapacitated , that he was able to restore the palatinate rights for the county of Lancaster . When Gaunt <a href='null_genetive' title='5'><mark>'s</mark></a>son Henry of Bolingbroke usurped the crown in 1399 and became Henry IV , the vast Lancaster inheritance , including the Lordship of Bowland , was merged with the crown as the Duchy of Lancaster . 
Lancaster was married to Isabella , daughter of Henry , Lord Beaumont , in 1330 . The 2 had no sons , but two daughters : Maud and Blanche . While Maud was married to William I , Duke of Bavaria , Blanche married Edward III  son John of Gaunt . Gaunt ended up inheriting Lancaster  possessions and ducal title , but it ain't till 1377 , when da dying King Edward III was largely incapacitated , that he was able to restore tdapalatinate rights fa thdaounty of Lancaster . When Gaunt  son Henry of Bolingbroke usurped the crown in 1399 and became Henry IV , the vast Lancaster inheritance , including thedardship of Bowland , was merged with the crown as the dahy of Lancaster .