It was never intended that Robert should run Cyfarthfa Ironworks. However, William Crawshay II placed him in charge after his oldest brother, William Crawshay III, drowned. Indeed, he was chosen over two older brothers. He was initially a popular man. However, a stroke in 1860 made him deaf and changed his personality to that of a tyrant, and he alienated both his workers and his family. When his eldest daughter, Rose Harriet, broke away from him to marry, Robert planned a spiteful revenge. He slipped a secret clause in his will disinheriting her children. Realising the cruelty of his actions, he instructed he be buried under a massive slab engraved with the words ‘God Forgive Me’.