The Llantysilio Hall MSS. consist mainly of the papers of Henry Robertson, the noted railway engineer, and of his son, Sir Henry Beyer Robertson. They include records relating to their estates in Denbighshire and Merionethshire and their wide-ranging business interests.
Henry Robertson (1816-1888), a Scotsman, first came to North Wales to assess the potential for the development of minerals in the Brymbo area for a Scottish bank. Following his assessment the bank offered to lend him the capital to take part in exploiting the mines himself. Several other young Scotsmen joined him and they formed the Brymbo Mineral Railway Company, which purchased the Brymbo Hall estate, including Brymbo ironworks. In 1846 the company was re-named the Brymbo Company, and W. H. and C. E. Darby were enlisted to take care of the pits and ironworks so that Henry Robertson could turn his attention to the railways, when he was engaged on the completion of the North Wales mineral railway. He also drew up plans for a viaduct over the Dee at Cefn, the through line to Shrewsbury being opened in October 1848. He was also involved in numerous other railway projects in the Midlands and Mid-Wales. By 1880 he had turned his attention to the possibility of producing steel at Brymbo and the first 10 ton steel melting furnace went into production in 1885. Between 1862 and 1885 he was elected three times as Liberal M. P. for Shrewsbury. On his election to parliament he purchased a house in London and a country residence called Crogen, a house situated on the Dee between Bala and Corwen. In 1869 he acquired the Pale mansion and estate near Corwen. He re-built the mansion and resided there from 1871. He was elected M. P. for Merioneth in 1885 but resigned and withdrew from the Liberal party on the introduction of Gladstone's Home Rule Bill. He was succeeded by his only son, Sir Henry Beyer Robertson (1862-1948), who was named after a friend of his father, Charles Frederick Beyer (1813-1876). He was Sir Henry's god-father and on his death bequeathed Llantysilio Hall, which he had purchased in 1867, to his god-son. Sir Henry spent some time assisting his father in his various business matters. He was responsible for many new developments at Brymbo steelworks including the installation of a new plant. During the First World War he ensured maximum production of iron and steel for munitions and Pale was turned into a military hospital. He was a director of several companies, including the Great Western Railway Company, and a member of the River Dee Fisheries Board. In 1890 he was granted a knighthood. His heir was his son, Duncan Robertson, of Llantysilio Hall.