The 9th Earl of Rosse, known as William Parsons, was an Irish nobleman born in 1900. He succeeded to the title in 1957 and was known for his contributions to astronomy and science. He was the last Earl of Rosse to hold the title, which was associated with the famous Leviathan of Parsonstown, a large telescope built by his ancestor, the 3rd Earl of Rosse. The 9th Earl was also involved in various charitable activities and served as a member of the House of Lords. He passed away in 1979, marking the end of the direct line of the Parsons family in the peerage. His legacy includes a continued interest in science and heritage in Ireland.