High Quality Content by WIKIPEDIA articles! Mat Roy Thompson (February 8, 1874–June 8, 1962), known also as Matt Roy Thompson, Matthew R. Thompson, Mathew R. Thompson, M. Roy Thompson, Roy Thompson, and Leroy Thompson, was a civil engineer and architect who worked on a great variety of construction and development projects across the United States, most notably on Scotty`s Castle, the Death Valley mansion of eccentric millionaire Albert Mussey Johnson.