For this act, Maurice was tried and attainted by the parliament in Dublin and his lands forfeited, but after his death they were restored to his brother John FitzMaurice, 5th Baron of Kerry.

However, these titles became extinct on his death in 1541 while he was succeeded in the Barony of Kerry by his younger brother.

The twenty-first Baron was created Earl of Kerry in the Peerage of Ireland in 1723.

His younger son John Petty Fitzmaurice was created the 1st Earl of Shelbourne in the Peerage of Ireland in 1753 and his son William Petty FitzMaurice, the 2nd Earl of Shelburne, who served as British prime minister from 1782 to 1783, was created Marquess of Lansdowne in 1784.

Earl of Kerry has subsequently been used as a courtesy title by heirs of the Marquess.