The scholarly study of personality development began with Sigmund Freud's writings on psychosexual development. Freud was the first to theorize on how personality developed over time, and during the early decades of the 20th century his view was the only game in town. However, other perspectives on personality development emerged after Freud's death in 1939. Harry Stack Sullivan, Erik Erikson, Henry Murray, Karen Homey, and others offered theories, some of which became enormously influential within personality, developmental, social, and clinical psychology. By midcentury, there was a plethora of personality development theories.