Art museum curator; authority on the folk art of the United States and the arts of Central America; director of the arts division of the WPA. Cahill was born to Bjorn Jonsson and Vigdis Bjarndottir in Iceland but moved with his family shortly after birth to Canada and then North Dakota, USA. Domestic violence and illness broke his family apart and Cahill spent most of his early years working and living in various situations and orphanages in Canada and the United States.

Bosch scholar and folk literature specialist. Fraenger's father was a judge and twice mayor of Erlangen, Emil Karl Hermann Fraenger; his mother was Wilhelmine Jacobine Fraenger. He entered the university in Heidelberg in 1910, beginning his art writing career with reviews of contemporary art shows for the Heidelberger Zeitung in 1912, including Alfred Kubin und Max Zachmann. Fraenger was awarded a prize by the University in 1913 for an essay, "Kunsttheorie des 17.