Old College, Aberystwyth, is one of Britain's most significant nineteenth century buildings, its development reflecting the evolution of architectural styles from the Picturesque Gothic of the 1790s to the Queen Anne Revival of the 1890s. The present building has its origins in Castle House, John Nash's first excursion into Gothic, designed to the specifications of Sir Uvadale Price, the leader of the late-18th-century Picturesque movement. In the 1860s, wings were added to the north and south of the house, with the intention of creating one of the most opulent hotels of the Railway Age. The bankruptcy of Thomas Savin, the Hotel's owner, in 1866 resulted in the Hotel being abandoned. The uncompleted building was then bought by the founders of the University College of Wales, and John Pollard Seddon was invited to adapt it for its new purposes. This study of a key Victorian building places Nash's Castle House in the context of the Picturesque Movement and provides an account of Seddon's ideas and architectural development. There is an assessment of the architecture of the Hotel, and also of Seddon's difficult relationships with his flamboyant entrepreneurial client and with the Council of the University College. This book, illustrated with photographs, plans and elevations, is intended to be of use not only to architectural historians, but also to all those concerned with Victorian studies, with the development of Welsh national consciousness and with the built environment of Wales. It should be of especial interest to the many former students who studied in the building.