The study of myth and religion became his areas of expertise. Except for visits to Italy and Greece, Frazer was not widely travelled. His prime sources of data were ancient histories and questionnaires mailed to missionaries and imperial officials all over the globe. Frazer's interest in social anthropology was aroused by reading E. B. Tylor's "Primitive Culture" (1871) and encouraged by his friend, the biblical scholar William Robertson Smith, who was comparing elements of the Old Testament with early Hebrew folklore.