Medievalist and first professor of art history at Stockholm University. Roosval was raised by successful middle-class parents in Stockholm, his father Consul John Roosval and mother Johanna Kramer. He entered Uppsala University in 1897 completing a degree in philosophy, languages, art history and Scandinavian philology in 1899. Roosval moved to Berlin to tutor Rolf de Maré, the son of Swedish military attaché there, Henrik de Maré.