The arms are those of Cathcart impaling those of Hamilton, as borne by Charles, 9th Baron Cathcart, born in 1721, the son of Charles, 8th Lord Cathcart and his first wife Marion, daughter of Sir John Shaw. Cathcart succeeded to the barony on the death of his father, of "a bloody flux," in 1740. His father's second wife married after her husband's death Hugh Macguire, an Irish officer in the Hungarian army, who, for twenty years, is said to have kept her a prisoner "in a lone castle in the fastness of Ireland."

Cathcart was ADC to the Duke of Cumberland at the Battle of Fontenoy in 1745 where he was severely wounded. He served as Colonel and Adjutant General to the British forces in North America in 1750 and was appointed a Major General in 1758. In 1768 he was sent as Ambassador to Russia, where he remained until 1771. He married, in 1753, Jean, daughter of Lord Archibald Hamilton and died, aged 56, in 1776.
.