Kenneth Bowser


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Western Sidereal Astrology, Part Two

The Dark Age, The Astrological Ages and The Ascendancy of the Tropical Zodiac in the West

A dark age is a step backward, a lower order of civilization than an earlier time.  The European Dark Age is so called because it was a time that was far less sophisticated than the Hellenistic (1) and the Roman Imperial (2) periods that preceded it. The European Dark Age refers approximately to the six centuries that extend from A.D. 400 to A.D. 1000.  It overlaps and is part of the Medieval Period or Middle Ages that extend loosely from A.D. 500 to A.D. 1500.  The six centuries of the Dark Age were characterized by an especially dismal intellectual torpor in Europe.  It was relieved modestly and briefly by the Carolingian Renaissance named after the best remembered figure of the Medieval Period, the emperor Charlemagne (crowned on Christmas day A.D. 800) who tried to revive the Roman empire.

During the Dark Age, there was no system of compulsory elementary education.  The overwhelming majority in every class of society was wholly illiterate and innumerate.  Naturally there were exceptions, especially among the clergy, but on a scale too small to affect the broader social fabric.  Moreover basic inquiry into the nature of the world —what might be called today basic scientific research, was strongly discouraged by the Catholic Church—the only institution from the Roman world to survive the Dark Age.  There was a paucity of astronomical observations and record-keeping during the Dark Age; no archives or libraries of any size or consequence were built or maintained except those of the Catholic Church; there were no great building or engineering projects; the rule of law was weak for lack of strong federal authority, and such authority as did exist was exercised mostly by the strongest local sword arm; trade and commerce were conducted at a modest level; plague and disease were rampant; public health systems did not exist; life was short, populations were small and did not increase; and the absence of  political coherence produced warfare that was endemic to the region.  Most important, knowledge that had been hard won through deduction and experiment over many centuries was lost. This cultural slump was particular to the West, not the entire world.

An example of the dismal state of astronomical knowledge in the West even before the fall of Rome is in the Roman calendar that was two days out of synchronization with the Sun as early as A.D. 354. (6)  The summer solstice in 354 was marked as June 24 but the Sun reached its maximum north declination on June 22 in that year.  This almost guarantees that nobody was taking celestial observations at the highest level of the Roman civil or ecclesiastical authority in 354 or in any other nearby year.  The last time that the solstice had occurred on June 24 of the Julian calendar was one hundred seventy-five years before in A.D. 179.

A bigger problem was that the date of the equinox was fixed by law as March 21 of the Julian calendar at the first ecumenical council of bishops at Nicaea (present day Iznik in modern Turkey) in May A.D. 325.  The Julian calendar consisted of 365 days with an extra day inserted every four years because the Julian year is 365.25 days long.  That was a good estimate of the length of the year for its era.  It was made by the astronomer Sosigenes, Julius Caesar’s calendar advisor at the time of the adoption of the Julian calendar (46 B.C.).  But the true length of the tropical year is 365.2422 days, which is 11 minutes and 14 seconds less than exactly 365.25 days.  There are 1440 minutes in a day which means that in 128 years, an extra day accrues in the Julian calendar that is not traversed by the Sun due to the difference between the length of the Julian year and the true length of the tropical year. (7) Thus, the true equinox slowly drifted away from its position in the Julian calendar prescribed by law.  During the lifetime of the Roman emperor Constantine I who convened the Council of Nicaea in A.D. 325, the true equinox occurred on March 20 or 21 of the Julian calendar.  By the seventh century the true equinox occurred on March 17 or 18.  By the time of the Gregorian Reform of the Julian calendar in 1582 the true equinox occurred on March 10 or 11 of the Julian calendar depending on leap year.  That is why ten days were dropped from the calendar: (October 4,1582 was followed by October 15, 1582) the most important day in the ecclesiastical calendar, Easter, was falling into winter. (8) There was no need to determine the day or time of the equinox because the church had decided that it was on March 21 into perpetuity.  Yet in the absence of the correct astronomical parameters, the equinox can only be determined by observation.  Almost surely, nobody in the West knew accurately where the equinox was in the Dark Age.

A similar kind of problem prevailed with the astrological ages during the Medieval Period.  The first point of Aries as defined by Hipparchos and Ptolemy is fixed on the Northern Hemisphere vernal equinox forever, even though that moment is the autumnal equinox in the Southern Hemisphere.  There is no moment of spring that is global.  Additionally, precession carried the Northern Hemisphere vernal equinox away from the stars in Aries just at the time when tropical and sidereal reckoning were coincident—which happens only once every 25,800 years.  Near in time to the transition from the Age of Aries to the Age of Pisces, Ptolemy, the leading astronomer of his day, was confident that he had astronomical reality firmly in hand except for some nagging details.  But there was no worthy successor to Ptolemy; and eventually the West was subsumed, astronomically speaking, under those nagging details.  Chief among them was an incorrect model of the solar system. That is, the Earth moves with respect to a fixed sky, not the other way around.  As the vigor of Roman civilization began to wane, the intellectual edge of the Roman world was quickly dulled by internal social, economic and political corruption, disdain for education and external military pressure.  In consequence, Ptolemy’s basic positions were not modified for almost fourteen centuries.

In stark contrast to the West at the beginning of the Age of Pisces, the trigonometric identities (sine, cosine and their inverses) and the concept of zero as more than a place holder, but a quantity, were being developed in a golden age in India (the Gupta Period: begin A.D. 320).  Engineering and building projects on a staggering scale and artistic sophistication of a very high order were the standard of the day there and in China (especially during the Tang dynasty), the Mayan Civilization and by the eighth century, the nation of Islam as well.  The Surya Siddhanta, perhaps the greatest Indian astronomical work composed during the European Dark Age, appeared in the sixth century of the current era; it was completely unknown in the West.  Later in the ninth and tenth centuries Muslim mathematicians completed the trigonometric identities with the discovery of the tangent, cotangent, secant and cosecant functions as well as quadratic equations, while the emperor Charlemagne was struggling to learn how to read.  Greek scientific and mathematical works that had been translated into Latin during the early periods of the Roman Empire stopped almost completely in the West for six hundred years with the fall of Rome, whereas such works were continuously translated into Sanskrit and later, Arabic during the same period.

Precession, described in part one of this series, is a westward movement.  Thus the ages are experienced against the order of the signs.  The Age of Aries that began in 1955 B.C. and ran until A.D. 220 was followed by the age of Pisces that runs from A.D. 221 to A.D. 2375; the Age of Aquarius begins in A.D. 2376.  One sees the end of the constellation first and the beginning last.  In 1955 B.C. the Age of Aries began when the Sun rose at the vernal equinox with 29° 59' in terms of sidereal reckoning.  The Sun rose at the equinox with 0° 00' in A.D. 220 again in terms of twelve equal length sidereal signs.  During an astrological age the Sun rises within the limits of the constellation of the age on the day of the Northern Hemisphere vernal equinox.  The change from age to age also points out a fact important to astrologers that is often not recognized: the astrological ages are entirely sidereal phenomena.  They have nothing to do with the tropical zodiac.

There are two kinds of zodiac boundaries to be considered for the ages.  The boundaries for the ages just mentioned are in terms of the zero degree of sidereal signs used by western siderealists.  This initial point conforms closely to the boundaries of the sidereal signs marked out by the Babylonian “normal stars,” or working stars that constitute the frame of reference of the ancient sidereal zodiac.  Like the Babylonians, western siderealists use a twelve-fold thirty degree equal division zodiac which is an approximation of the unequal divisions of the astronomical zodiac.  It is not necessary that the zodiac of the sidereal signs conforms exactly to the astronomical zodiac but rather that the sidereal frame of reference does not precess and stays aligned with the stars of the zodiac, an epoch and the galactic center (due to the rotation of the ecliptic itself [47” per century]). 

The sidereal signs of equal length are known by the Greek name, zodia noeta, which means, “intelligible zodiac signs.”  It is these signs that correspond to the aforementioned dates of entry and exit to and from the astrological ages.  The earlier unequal length signs are known as the morphomata, another Greek name for “that which has form.”  The equinox first entered the astronomical constellation Pisces (as defined in A.D. 1922 by the International Astronomical Union) in 68 B.C. and will not enter the territory of the astronomical constellation Aquarius until A.D. 2597.  It is noteworthy that whether one invokes sidereal signs of equal length that correspond nearly to the actual constellation boundaries or the actual but unequal boundaries of the constellations as defined by a modern standard, the Age of Aquarius that many people consider near is almost four hundred years into the future at the earliest and almost six hundred at the latest.

The Almagest was beyond the understanding of all but the most talented minds during the Middle Ages, almost all of whom were also beyond the borders of Christendom, due to the educational deficiencies of the West (until the first European universities were established in the eleventh and twelfth centuries).  Ptolemy’s Handy Tables and Theon’s Handy Tables were mostly used by astrologers well into the late Middle Ages.  What passed for a medieval education was the compilation of a fifth century writer who wrote after the sack of Rome in 410, which he mentioned, but before the Vandals conquered North Africa in 429.  This man, Martianus Felix Capella, variously described as a farmer and a lawyer, put together in Latin an often misinterpreted and extremely verbose summation of the knowledge of the known world up to his time entitled, On the Wedding of Philology and Mercury and the Seven Liberal Arts in Nine Books. The seven liberal arts were grammar, dialectic, rhetoric, geometry, arithmetic, astronomy and musical harmony.  Some of the information is good and accurate; much is wrong, badly explained, misunderstood or expressed in bizarre fashion.  Despite its popularity Capella’s work was a pale imitation of the intellectual excellence that preceded his time.  The geometry, for example, is incomplete, misquoted (from Euclid’s Elements) and without proofs.  The book book was full of scribal errors that were compounded with every new copy.

Given the intellectual climate in the West during the Medieval Period it is entirely unreasonable to expect astrological sophistication, understanding and advance during that time. The condition of the age was not amenable to the widespread dissemination of knowledge.  It was only when ancient Greek texts that had been translated into Arabic began to be retranslated into Greek and especially Latin that astrology was re-examined by newly educated literate westerners in the twelfth century.  The Almagest was not translated into Latin for the first time until A.D. 1160.  The new European enthusiasts were an exceptional group because there were no astrological texts in the vernaculars of the day; rather, astrology was available to Latin, Greek, Arabic or Sanskrit speakers.  Astrology became the province of educated men who were not only literate in European vernaculars but also Latin, the language of scholarship.  The only authority available to the overwhelming majority of Europeans was Ptolemy.  India and China were unknown quantities.  The closest neighbor of Christendom, the nation of Islam, thoroughly embraced Ptolemaic astronomy/astrology.  Tropical astrology therefore had no competition for many centuries.

Furthermore most of the zodiac could be described in terms of the tropical signs until A.D. 1301.  That is the half-way point of the Age of Pisces.  Before that year, more than half of all people born with the Sun in tropical Aries had the Sun in sidereal Aries too.  After 1301 more people were born with the Sun in sidereal Pisces when the Sun was in tropical Aries than before that date.  Precession accrues at the rate of one degree per seventy-two years.  Therefore during less than the course of an average American lifetime, the displacement between the tropical and sidereal zodiacs increases by one degree.  Five out of six people born in 2007 who have the Sun in tropical Aries have it in sidereal Pisces.  In 369 years at the dawn of the Age of Aquarius, all tropical Ariens will be sidereal Pisceans.

(1) The Hellenistic Period dates from the death of Alexander the Great in 323 B.C. until Octavian’s victory over Antony and Cleopatra at the Battle of Actium in 31 B.C.

(2) The Roman Imperial Period dates from the total Roman control of the Italian peninsula in 264 B.C and subsequent expansion until the death of the emperor Marcus Aurelius in A.D. 180.

(3) A West Germanic barbarian tribe that invaded the Roman Empire in the fourth century.

(4) An East Germanic barbarian tribe that invaded the Roman Empire in the fifth century.

(5) Theon of Alexandria A.D. 335 – 405, mathematician and author of explanations of how to use both Ptolemy’s Almagest and Ptolemy’s Handy Tables which are themselves explanations of how to use the Almagest in simplified form.  Both Ptolemy’s and Theon’s Handy Tables were in wider circulation in Late Antiquity and the Medieval Period than the Almagest.

(6) Michele Renee Salzman, On Roman Time (Berkeley: University of California Press, 1990), 183.

(7) The tropical year is the time elapsed between consecutive conjunctions of the Sun with the vernal equinox.  It is 365 days, five hours 48 minutes and 46 seconds.

(8) There was an ever-worsening problem around the need for the Resurrection to coincide with spring and the Easter computus whereby Easter is the first Sunday after the first full Moon after the Northern Hemisphere vernal equinox.

© Kenneth Bowser, 2007.  Adapted from An Introduction to Western Sidereal Astrology (AFA 2012) To purchase the new edition of this book on, click here

Part Three will address the rediscovery of Babylonian sidereal astrology in the 19th century and how it arrived on the astrological scene through the efforts of Cyril Fagan in the twentieth century.