The 3rd Marquess of Bute, another John Crichton-Stuart, inherited the castle and the family estates as a child in 1848. On his coming of age, Bute's landed estates and industrial inheritance made him one of the wealthiest men in the world. He had a wide range of interests including archaeology, theology, linguistics and history. Interest in medieval architecture increased in Britain during the 19th century, and in 1850 the antiquarian George Clark surveyed Castell Coch and published his findings, the first major scholarly work about the castle. The ruins were covered in rubble, ivy, brushwood and weeds; the keep had been largely destroyed and the gatehouse was so covered with debris that Clark failed to discover it. Nonetheless, Clark considered the external walls "tolerably perfect" and advised that the castle be conserved, complete with the ivy-covered stonework.