Apollo and Dionysus were gods in ancient Creek religion. More to the point, the were both gods in the Ancient Greek pantheon, despite representing nearly opposing values and orientations.
“Apollonian” and “Dionysian” are terms used by Friedrich Nietzsche in The Birth of Tragedy to designate the two central principles in Greek culture. Nietzsche characterizes the differences this way:
The Apollonian: analytic distinctions
All types of form or structure are Apollonian, thus, sculpture is the most Apollonian of the arts, since it relies entirely on form for its effect. Rational thought is also Apollonian since it is structured and makes distinctions.
The Dionysian: inability or unwillingness to make these distinctions; directly opposed to the Apollonian
Drunkenness and madness are Dionysian All forms of enthusiasm and ecstasy are Dionysian. Music is the most Dionysian of the arts, since it appeals directly to man's instinctive, chaotic emotions and not to his formally reasoning mind.
Dionysus was said to be the son of Zeus and the mortal Semele. His mother
died before he was born so he was cared for by the maenads, or bacchantes.
This became the cult of females who devoted themselves to the care and worship
of the god. The festivals associated
with them (the bacchanals) were ecstatic affairs where participants would be
given to inspirations and divine enthusiasms.
The word “maenad” comes from the Greek, meaning "mad." The religious rites of the maenads were
orgiastic; they are said to have roamed the countryside performing frenzied
dances possessed by the god himself.
During the trances they were supposed to have superhuman strength, to
tear animals or people to pieces. (The
Bacchantes they were named for Bacchus, the Roman counterpart of
Dionysus.) These rites became the
origins of “tragic drama” in ancient
The worship of Dionysus is thought to have come to
Note the opposition: Apollo is representative of principle and calm reason. Dionysus is the representative of mad inspiration, an inability to discern the boundaries between appearance and reality. Apollo represents the state of "measured restraint," in which one remains separate from and thus mastery over the emotions; Dionysus represents a surrendering of self- where “self” is conceived of in roughly Platonic terms, as the rational ego. Thus, Dionysus is associated with drunkenness, the state in which one enters into an “inspiration,” an ecstatic unity, an identification (perhaps with a higher entity or community).
Using these terms we can see that Platonism and Neo-Platonism clearly advocated Apollonian values and denigrated the Dionysian. It is also worth mentioning that the Dionysian values are often associate with females and the feminine. Keep in mind that “female hysteria” was a common medical diagnosis, made exclusively in women, which dates back to ancient Greece. Women have long been portrayed as more sensitive, emotional and more “physical” (limited and/or determined by their bodies) then men. These features in turn are regarded as lamentable shortcomings in women or men.
Nietzsche however believed that both forces were present in Greek tragedy, and that a true tragedy could only be produced by the tension between them. Thus Nietzsche argues that aesthetics is not merely a "merry diversion." He sees the artistic enterprise as inextricably bound with the Apollonian and Dionysian duality. While this clash may be destructive, it is also the source of creativity and procreation, necessary for health and wellbeing.
Nietzsche uses this duality for discussing the artistic process which relate to either Apollo or Dionysus. Apollo and Dionysus symbols of this duality which he further distinguishes with the terms of “dreams” and “drunkenness.” For Nietzsche, dreams represent the realm of beautiful forms and symbols, an orderly place of light and reason. Drunkenness, on the other hand, is that state of wild passions where the boundaries between "self" and "other" dissolve. (This may strike as odd, but Nietzsche seems to make the assumption that, when dreaming, one is aware of the fact that one is dreaming and so still able to separate appearance from reality. I believe that he would claim those who are entirely caught up in their dreams are experiencing Dionysian ecstasy, not Apollonian beauty.)
Nietzsche, held that the Dionysian resulted from the absence of the Apollonian (and not the other way around) so in a sense the Apollonian held a kind of primacy. Indeed the Greeks themselves held that Apollo was the superior God. Apollo was infuriated when the satyr (a devotee of Dionysus and flute-player) Marsyas challenged Apollo to music contest. After winning the competition, Apollo had Marsyas flayed alive, for being so presumptuous, as to challenge a god.
"The Flaying of Marsyas" by Titian: http://www.mansfield.edu/~art/Papyrus3SylviaMinarovicTitian_and_the_flaying_of_marsya.htm
"Apollo Skinning Marsyas" by Jose de Ribera: http://www.pandorawordbox.com/image.php?image=011637227
This is certainly a graphic potential of the strife between the two poles. One should also note the unsettling clam of the Apollo figure in each painting as he does the nearly unthinkable. One might read this as a cautionary tale, that it is Dionystic compassion and sympathy and NOT cool reason, that prevents us from our most monstrous crimes.
Nevertheless. Apollo and Dionysus were brothers (sons of
Zeus), each was Divine, and curiously each was a musician- Apollo the Lyre and
Dionysus the Flute. Similarly, Nietzsche
sees the Dionysian consciousness as crucial to artistic creation. He refers to
those who would condemn the ecstatic celebrations of
"Such poor wretches can not imagine how anemic and ghastly their so-called 'healthy-mindedness' seems in contrast to the glowing life of the Dionysian revelers rushing past them."
One must submit to Dionysian madness in order to attain the state of primordial unity, a state beyond social barriers and narrow thinking.
 The production and appreciation of the Arts has traditionally been associated with effeminacy- not in the current sexual sense, but in the older sense of a “softness” and the an inability and/or unwillingness to withstand difficulty, hardship and pain. The virtue (for men and women, but especially for men) of courage was not considered so much an emotion, but an ability to resist emotion in light of reason. This habit of mind was thought to be undermined by art which appeals to emotion.
Effeminacy, more than a personal failing, had political implications. This characteristic would determine if one’s society was free or slavish. Greeks attributed this quality to the Asiatics because they lived under tyranny. Self-government was seen as a product of manliness.
Herodotus tells the story of the King of Persia who wanted to kill all the males of Lydia to keep them from revolting. Evidently the Lydian King, Croesus, counter-proposed that instead Cyrus make the males docile and soft commanding them to learn lyre-playing and song and dance.
“Then, O King, you will soon see them turned to women instead of men; and thus you need not fear lest they revolt." Herodotus Book I p. 155
 From Plato’s Timaeus: http://www.gutenberg.org/files/1572/1572-h/1572-h.htm
The divine soul God lodged in the head, to raise us, like plants which are not of earthly origin, to our kindred; for the head is nearest to heaven. He who is intent upon the gratification of his desires and cherishes the mortal soul, has all his ideas mortal, and is himself mortal in the truest sense. But he who seeks after knowledge and exercises the divine part of himself in godly and immortal thoughts, attains to truth and immortality, as far as is possible to man, and also to happiness, while he is training up within him the divine principle and indwelling power of order. There is only one way in which one person can benefit another; and that is by assigning to him his proper nurture and motion. To the motions of the soul answer the motions of the universe, and by the study of these the individual is restored to his original nature.
Thus we have finished the discussion of the universe, which, according to our original intention, has now been brought down to the creation of man. Completeness seems to require that something should be briefly said about other animals: first of women, who are probably degenerate and cowardly men. And when they degenerated, the gods implanted in men the desire of union with them, creating in man one animate substance and in woman another in the following manner:—The outlet for liquids they connected with the living principle of the spinal marrow, which the man has the desire to emit into the fruitful womb of the woman; this is like a fertile field in which the seed is quickened and matured, and at last brought to light. When this desire is unsatisfied the man is over-mastered by the power of the generative organs, and the woman is subjected to disorders from the obstruction of the passages of the breath, until the two meet and pluck the fruit of the tree.
 St. John’s Dance or St. Vitus Dance refers to a document phenomenon of manic dancing that historically took place Germanic and Latvian cultures.