400 - 300 B.C.

Greek philosophers begin doing what they do best using the tools they use best : speculation and introspection. Among them are Socrates, Plato and Aristotle.

1600's

1679 : Christian Wolff, inventor of the term psychology is born.

1700's

1724 : Immanuel Kant is born.
1754 : Christian Wolff, inventor of the term psychology, dies.
1773 : Jakob Fries is born.
1776 : Johann Herbart is born.
1798 : Eduard Beneke is born.

1800's

1879 : Wilhelm Wundt founds the first psychological research laboratory in Leipzig, Germany. This is considered to be the exact time where psychology became a science by relying on research rather than philosophical introspection.
1886 : Sigmund Freud starts his practice in Vienna, Austria.
1888 : At the University of Pennsylvania, James McKeen Cattell becomes the first professor of psychology.
1892 : Stanley Hall gathers up 41 of his friends and forms the American Psychological Association.
See the entire 1800's timeline.

1900's

1900 : Sigmund Freud publishes The Interpretation of Dreams, the first outline of some of his most well-known ideas, including: the Id, Ego, Superego, and the Oedipus Complex.
1901 : British Psychological Society is formed.
1906 : Ivan Pavlov publishes his research on classical conditioning.
1952 : The first edition of the DSM is published.
1980 : DSM-III is published.
1994 : DSM-IV is published.