On the death of his younger son, the fourth Baron, this line of the family failed.
His son, the sixth Baron, assumed in 1938 by deed poll the additional surname of Conolly, which was that of his maternal grandfather.
The seventh Baron was a distinguished equestrian, who represented Ireland in the Olympic Games.
As of 2024[update] the titles are held by his son, the eighth Baron, who succeeded in that year.
Between 1956 and 1965 the sixth Baron was the owner of Castletown House and Estate in County Kildare, regarded as one of Ireland's finest country houses and now a museum open to the public and in the ownership of the Irish State.