Young & Mackenzie, Architects, Donegall Square West, Belfast, 1825-1937. The firm was founded by the Rt Hon. Robert Young (1822-1917), architect and civil engineer, who articled with the renowned architect, Charles Lanyon, and afterwards was his chief assistant in carrying out important engineering works, including the Belfast and Ballymena Railway. Settling in his home town of Belfast in the early 1850s, he established the business in 1854 in partnership with John Mackenzie, being joined later by his son, Robert, who made a huge personal contribution to the work of the practice by his design of numerous nineteenth century buildings including: many Ulster Presbyterian churches, manses and schools; mansions and large warehouses; hospitals for several public authorities and well-known buildings. The firm is no longer in operation.