Arthur spent 40 years in the British Army at various posts in her majesty's empire. He was appointed viceroy (Governor General) of Canada by his nephew George V and served there in World War One. Then he returned to the United Kingdom, and there and in India, performed various royal duties until his retirement in 1928. He died in 1942 at the age of 91.
It is said he became the queen's favorite child. While in the army stationed in Canada, he attended balls and garden parties and visited towns in Ontario and Quebec. These things were all documented by photographs which were sent back for his mother to enjoy. Someone told Queen Victoria that the Canadians hoped Arthur would someday return as their Governor General. He did.
Arthur married a Prussian princess and they had three children.
In addition to his 40 years of military service, during which he rose to the rank of general, then field marshall, he also:
was elected Grand Master of the United Grand Lodge of England, and
commissioned a stained glass window in his family's memory which he had placed in St. Bartholomew's church, where his family attended services.
Earlier, in Canada, Arthur had laid a cornerstone to a new government building.
In later life, Arthur became president of the Boy Scouts Association and performed the official opening of the 3rd World Scout Jamboree.
The duke retired from all this in 1928.