At the death of the 2nd Lord there were two possible heirs: his grandson who was created ''Baron Castle Stuart'' in the Peerage Of England (?not really?) Or Ireland . At the death of the 5th Baron the barony became dormant in 1685 . The 9th Baron (de jure) was officially restored to the barony (?) and created ''Earl Castle Stewart / Stuart'' in 1800 . The subsidiary title of the earldom is ''Viscount Castle Stuart / Stewart'' (1793). Both titles are created in the Peerage Of Ireland .
The Lordship of Parliament was finally gained by another grandson of the 2nd Lord by the son who had gained the ''Earldom of Arran'' for a short time. At the death of the 5th Lord it became extinct in 1675 .
The Courtesy Title of the earl's (Castle Stuart) is ''Viscount Stuart''.
