The Four Horsemen of the Apocalypse

The word Apocalypse means "uncovering", which is synonymous with the word Revelation - "to reveal".

(Revelation 6:2) "And I looked, and behold, a white horse. He who sat on it had a bow; and a crown was given to him, and he went out conquering and to conquer".
(Revelation 6:4) "Another horse, fiery red, went out. And it was granted to the one who sat on it to take peace from the earth, and that people should kill one another; and there was given to him a great sword".
(Revelation 6:5–6) "So I looked, and behold, a black horse, and he who sat on it had a pair of scales in his hand. And I heard a voice in the midst of the four living creatures saying, 'A quart of wheat for a denarius, and three quarts of barley for a denarius; and do not harm the oil and the wine' ".
(Revelation 6:8) "So I looked, and behold, a pale horse. And the name of him who sat on it was Death, and Hades followed with him. And power was given to them over a fourth of the earth, to kill with sword, with hunger, with death, and by the beasts of the earth".

There are 12 zodiac 'houses'  - three attributed to each aspect of the four seasons. Each season consists of one cardinal (waxing, or ascending) house, one fixed (stable) house, and one mutable (waning, or declining) house. In the yearly transit of the sun through the zodiacs, each of the 12 zodiacs is referred to as a house (Beth in Hebrew). In relation to the Great Year (explained later), each of these is referred to as an Age (Olam in Hebrew).

It is said that each house is ruled over by a corresponding planet, which adds its influence to the sign it rules over. These are as follows:

Venus rules over Taurus and Libra

The Sun rules over Leo

The Moon rules over Cancer

Mercury rules over Gemini and Virgo

Mars rules over Scorpio and Aries

Jupiter rules over Sagittarius and Pisces

Saturn rules over Aquarius and Capricorn

The Four Horsemen of the Apocalypse represent the four seasons - the four fixed zodiacs, as follows:

The Calf = Taurus, representing Spring, the white horseman, is ruled by Venus

The Lion = Leo, representing Summer, the red horseman, is ruled by the Sun

The Eagle = Scorpio, representing the Fall, the black horseman, is ruled by Mars

The Man = Aquarius, representing Winter, the grey horseman, is ruled by Saturn

The horses represent the cardinal (ascending, or waxing) signs of the zodiac, which carry the new season forward, whereas their riders represent the fixed (stable) season themselves. Together these become the four Horse-Men.

Taurus (the Spring rider) rides upon the white horse Aries. The sign Aries begins on March 21, which is the first day of the Spring Equinox, marking the first day of Spring. The color white symbolizes virginity and the clear intentions - the lamb. Thus the first rider - Taurus - rides Aries through Spring to the threshold of Summer. Taurus is ruled by the negative influences of Venus: unbridled lustful desires. Taurus was the conqueror, denoting the spring's victory over winter (death).

Leo takes over at the Summer Solstice. Leo (the Summer rider) rides upon the fiery horse Cancer. The sign Cancer begins on June 21, which is the first day of the Summer Solstice, thus in turn marking the first day of summer. Red symbolizes the crab as well as the blazing summer sun. Leo rides Cancer through the summer to the gates of Autumn. Leo is ruled by the negative aspects of the Sun: its scorching, burning influence. It also embodies the duality of opposing elements: fire and water, which are signified as the two asses used in the symbol of the zodiac Cancer.

Scorpio (the Autumn rider) rides upon the black horse Libra. The sign Libra begins on September 23, which is the first day of the Autumn Equinox, marking the first day of fall. Black symbolizes the increasing darkness as the days grow shorter. Scorpio is also known as the Eagle constellation. The third rider - Scorpio - rides Libra right up to the doorstep of Winter. Scorpio is ruled by the negative influences of Mars: rash, harsh judgments based on false accusations leading to condemnation. In the black rider's hands he holds the scales, denoting the judgment of the labors and sins of men, both material and spiritual, good and bad. He is the one who judges those accused by Satan - whose name means the accuser, who after having enticed mankind throughout the year, now stands accusing and demanding justice against those whom he had seduced into sin. 

Aquarius (the Winter rider) rides upon the pale horse Capricorn. The sign Capricorn begins on December 21, which is the first day of the Winter Solstice, marking the beginning of winter. Grey symbolizes the ashen color of the dormant earth and of death, as well as the gloomy mist and heavy clouds through which the dying son struggles to reach us. The fourth rider - Aquarius - rides Capricorn to the steps of Spring. Aquarius is influenced by its ruler Saturn, whose negative aspect is the death and damnation of those previously found guilty.

The four riders are the four fixed signs, denoting the peak of their respective seasons, and each of these four is complimented by a sign on each side: in the yearly (clockwise) transit of the sun, the preceding sign of each is called the cardinal sign, which announces the season to come (Aries to Taurus = the first horse-man: Cancer to Leo = the second horse-man: Libra to Scorpio = the third horse-man; and Capricorn to Aquarius = the fourth horse-man).

The period in which the rider and the horse unify is called a cusp (for example, the days when the sun transits from Aries into Taurus is called the Aries-Taurus cusp). This signifies the point of transition between two signs, when the previous sign's influence begins to decrease in contrast to the next sign increasing. This denotes the yearly transit of the sun through the seasons and their respective houses, from spring through winter, based upon the celestial calendar which begins in Aries at the Spring Equinox. 

In Revelation, the four beasts (the fixed houses of the zodiac), are said to have many eyes fore and aft... these ''eyes'' ''fore'' and ''aft'' are the stars of the cardinal (waxing: increasing) and mutable (waning: decreasing) houses of the zodiac that come before and follow after each fixed house: the stars in Cancer and Virgo, for example, are the ''eyes'' ''fore'' and ''aft'' of Leo.