Four Temperaments
Four Temperaments is a theory of psychology that stems from the ancient concept of four humors (humorism).

# History and development
Temperament theory has its roots in the ancient four humors theory of the Greek doctor Hippocrates (460-370 BC), who believed certain human behaviors were caused by body fluids (called "humors"): blood, yellow bile, black bile, and phlegm. Next, Galen (131-200) developed the first typology of temperament in his dissertation De temperamentis, and searched for physiological reasons for different behaviors in humans. Nicholas Culpeper (1616-1654) was the first to disregard the idea of fluids as defining human behavior, and Immanuel Kant (1724-1804), Rudolf Steiner (1861-1925), Alfred Adler (1879-1937), Erich Adickes (1866-1925), Eduard Spranger (1914), Ernst Kretschmer (1920), and Erich Fromm (1947) all theorized on the four temperaments (with different names) and greatly shaped our modern theories of temperament. Hans Eysenck (1916-1997) was one of the first psychologists to analyze personality differences using a psycho-statistical method (factor analysis), and his research led him to believe that temperament is biologically based. The factors he proposed in his book Dimensions of Personality were Neuroticism (N) which was the tendency to experience negative emotions, and the second was Extraversion (E) which was the tendency to enjoy positive events, especially social ones. By pairing the two dimensions, Eysenck noted how the results were similar to the four ancient temperaments.
- High N, High E = Choleric
- High N, Low E = Melancholic (also called "Melancholy"/pl. "-ies")
- Low N, High E = Sanguine
- Low N, Low E = Phlegmatic
Other researchers developed similar systems, many of which did not use the ancient temperament names, and several paired extroversion with a different factor, which would determine relationship/task-orientation. Examples are DiSC assessment, Social Styles, and a theory that adds a fifth temperament. One of the most popular today is the Keirsey Temperament Sorter, whose four temperaments were based largely on the Greek gods Apollo, Dionysus, Epimetheus and Prometheus, and were mapped to the 16 types of the Myers-Briggs Type Indicator (MBTI). They were  renamed (SP=Artisan, SJ=Guardian, NF=Idealist, NT=Rational). Rather than using extroversion and introversion (E/I) and task/people focus, like other theories, KTS mapped the temperaments to "Sensing" and "Intuition" (S/N, renamed "concrete" and "abstract") paired with a new category, "Cooperative" and "pragmatic" (loosely based on Judging and Perception, or J/P). When "Role-Informative" and "Role-Directive" (loosely connected with Thinking/Feeling or T/F, and corresponding to people/task-orientation), and finally E/I are factored in, you attain the 16 types. Finally, the Interaction Styles of Linda V. Berens combines Directing and Informing with E/I to form another group of "styles" which greatly resemble the ancient temperaments, and these are mapped together with the Keirsey Temperaments onto the 16 types.

# The four personality types
Each of the four types of humours corresponded to a different personality type.

## Sanguine
Sanguine indicates the personality of an individual with the temperament of blood, the season of spring (wet and hot), and the classical element of air.  A person who is sanguine is generally optimistic, cheerful, confident, popular, and fun-loving. He/She can be day-dreamy and off-task to the point of not accomplishing anything and can be impulsive, possibly acting on whims in an unpredictable fashion. Sanguine people usually have a lot of energy, but have a problem finding a way to direct the energy. This also describes the manic phase of a bipolar disorder.

## Choleric
Choleric corresponds to the fluid of yellow bile, the season of summer (dry and hot), and the element of fire.  A person who is choleric is a doer and a leader. They have a lot of ambition, energy, and passion, and try to instill it in others. They can dominate people of other temperaments, especially phlegmatic types. Many great charismatic military and political figures were cholerics.  On the negative side, they are easily angered or bad tempered.
In folk medicine, a baby referred to as having "colic" is one who cries frequently and seems to be constantly angry.  This is an adaptation of "choleric," although no twentieth/twenty-first century scholar or doctor of medicine would attribute the condition to bile.  Similarly, a person described as "bilious" is mean-spirited, suspicious, and angry.  This, again, is an adaptation of the old humour theory "choleric."
The disease Cholera gained its name from choler (bile).

## Melancholic
Melancholic is the personality of an individual characterized by black bile; hence (Greek , melas, "black", + , khole, "bile"); a person who was a thoughtful ponderer had a melancholic disposition.  Often very kind and considerate, melancholics can be highly creative - as in poetry and art - but also can become overly pre-occupied with the tragedy and cruelty in the world, thus becoming depressed. The temperament is associated with the season of autumn (dry and cold) and the element earth. A melancholy is also often a perfectionist, being very particular about what they want and how they want it in some cases.  This often results in being unsatisfied with one's own artistic or creative works and always pointing out to themselves what could and should be improved.
This temperament describes the depressed phase of a bipolar disorder.
There is no bodily fluid corresponding to black bile; the medulla of the adrenal glands, which decomposes very rapidly after death, can be associated with it.

## Phlegmatic
A phlegmatic person is calm and unemotional.  Phlegmatic means "pertaining to phlegm", corresponds to the season of winter (wet and cold), and connotes the element of water.
While phlegmatics are generally self-content and kind, their shy personality can often inhibit enthusiasm in others and make themselves lazy and resistant to change.  They are very consistent, relaxed, rational, curious, and observant, making them good administrators and diplomats.  Like the sanguine personality, the phlegmatic has many friends. However the phlegmatic is more reliable and compassionate; these characteristics typically make the phlegmatic a more dependable friend.

## Historical Development

# Decline in popularity
When the concept of the temperaments was on the wane, many critics dropped the phlegmatic, or defined it purely negatively as the absence of temperament. This, however, made it available for the German philosopher Immanuel Kant to reclaim as the temperament appropriate to freedom and virtue. In the Five Temperaments theory, the classical Phlegmatic temperament is in fact deemed to be a neutral temperament, whereas the "relationship-oriented introvert" position traditionally held by the Phlegmatic is declared to be a new "fifth temperament."

# Modern adaptations
Christian writer Tim LaHaye has attempted to repopularize the ancient temperaments through his books.  In Waldorf education and anthroposophy, the temperaments are used to help understand personality. They are seen as avenues into teaching, with many different types of blends, which can be utilized to help with both discipline and defining the methods used with individual children and class balance.

## Temperament Blends
LaHaye believes there are twelve mixtures of the four temperaments, representing people who have the traits of two temperaments, called Mel-Chlor, Chlor-San, San-Phleg, Phleg-Mel, Mel-San, Chlor-Phleg; and the reverse of these: Chlor-Mel, San-Chlor, Phleg-San, Mel-Phleg, San-Mel, and Phleg-Chlor. The order of temperaments in these pairs was based on which temperament was the "dominant" one (this is usually expressed by percentages). A person can also be a blend of three temperaments. Other four-type models, such as Social Styles, also have similar blends q.v., and in the five temperament theory, the blends are defined along the three areas of "Inclusion", "Control", and "Affection". The blends expand the number of types to 16 (12 blends of 2 types, plus the four pure types) or more (for blends of three).

# In fiction and the Arts
Rupert Thomson's fiction novel "Divided Kingdom" is set in an alternate Britain where the population has been segregated on the basis of which of the four temperaments their character belongs.
"Four Temperaments" is also the name of a 1946 ballet choreographed by George Balanchine for his company Ballet Society (now New York City Ballet).
In the White Wolf, Inc. game Promethean: The Created each of the five types of promethean has a temperament associated with them.  There is also a fifth temperament associated with a  fifth element spirit.  The fifth temperament's associated body fluid is  ectoplasm and the associated organ is the Pineal gland.