Augustus Charles Lennox, Knight of the Garter. Entered the army in 1837, by joining the 60th Rifles. Two years later found him in the Coldstream Guards of which, after a distinguished military career in which he took part in the Crimean Campaign and was severely wounded at Inkerman, the bullet, which entered his jaw and passed out at the back of his neck, missing his spine by a fraction of an inch. He became a General in 1881. The Duke seemed to bear a charmed life, recovering from critical illnesses which would have carried off one of less sturdy constitution.

The Duke's eldest son Lord Euston died in 1912, but not until December 4th 1918, when he had attained the age of 97, did the grand old man give up his earthly struggle. For thirty-three years he had been equerry to Queen Victoria, who conferred on him the Order of the Garter as a personal favour. He had never been a political partisan and only on being assured that no political consideration had influenced the award, did he accept the honour. A kind hearted man, he brought under the notice of the Royal Agricultural Society a scheme for the abolition of the practice of docking horses. His taste was for the useful rather than the artistic. He sold all the much prized Chippendale furniture. On Saturday, April 5th, 1902, fire destroyed part of Euston Hall, but while valuable historic papers were lost, the furniture and pictures were saved.

Among his other many notable appointments, His Grace was also Ranger of Whittlebury Forest, J.P., for Suffolk and Bucks, and County Alderman for Northampton until 1906.

He was succeeded by his second son Alfred William Maitland FitzRoy.