From 1863 onwards, although Armstrong remained the head of his company, he became less involved in its day-to-day running. He appointed several very able men to senior positions and they continued his work. When he married, he acquired a house called Jesmond Dean (sic), which is now demolished, and not to be confused with the nearby
Jesmond Dene House. Armstrong's house was to the west of
Jesmond Dene, Newcastle, and thus not far from his birthplace, and he began to landscape and improve land that he bought within the Dene. In 1860 he paid local architect
John Dobson to design a
Banqueting Hall overlooking the Dene, which still survives, though it is now roofless. His house close to Newcastle was convenient for his practice as a solicitor and his work as an industrialist, but when he had more spare time he longed for a house in the country. He had often visited
Rothbury as a child, when he was afflicted by a severe cough, and he had fond memories of the area. In 1863 he bought some land in a steep-sided, narrow valley where the Debdon Burn flows towards the
River Coquet near Rothbury. He had the land cleared and supervised the building of a house perched on a ledge of rock, overlooking the burn. He also supervised a programme of planting trees and mosses so as to cover the rocky hillside with vegetation. His new house was called
Cragside, and over the years Armstrong added to the Cragside estate. Eventually the estate was and had seven million trees planted, together with five artificial lakes and of carriage drives, and his demonstration centre at Cragend Farm Hydraulic Silo. The lakes were used to generate hydro-electricity, and the house was the first in the world to be lit by hydro-electricity, using incandescent lamps provided by the inventor
Joseph Swan. As Armstrong spent less and less time at the Elswick works, he spent more and more time at Cragside, and it became his main home. In 1869 he commissioned the celebrated architect
Richard Norman Shaw to enlarge and improve the house, and this was done over a period of 15 years. In 1883 Armstrong gave
Jesmond Dene, together with its banqueting hall to the city of Newcastle. He retained his house next to the Dene. Armstrong entertained several eminent guests at Cragside, including the Shah of
Persia, the King of
Siam, the prime minister of China and the
Prince and
Princess of Wales. ==Later life==