their 'firstborn' [='eldest, oldest'] child
Parents often spoil their 'firstborns'.
(..) Lady Crane: My firstborn son. My child king, hush. Listen to the gods, for you they sing. Fight no more, sweet child. Your wars are won. The wolves are buried and the false stag done. Shut your blue eyes, my love. Let the crown fall. (..)2016 TvShow: Game of Thrones Title: No One Season: 6 Episode 8