astrology ............................................
Astrology, the study of the planets and
their position in order to predict future
events, has its origins in ancient Babylo-
nia. The basic principles of astrology as set
out in theTetrabiblosof Ptolemy, the Al-
exandrian astronomer of the second cen-
tury, formed the basis of astrology as it
was practiced in the Middle Ages. Planets,
the “wanderers” of the night sky, were be-
lieved to have certain characteristics that
had a corresponding affect on earth. Sat-
urn, for example, was considered a cold,
dry, and harmful planet, while the moon
was viewed as warm, moist, and beneficial.
The position of the planets relative to each
other, and their motion along the ecliptic
plane or zodiac, also came into play.
The complexities of this system made
it a difficult and esoteric science, under-
standable only to educated men and out
of the reach of commoners. An occult
mystique surrounded astrologers, who
seemed to have access to hidden knowl-
edge of how the universe really worked.
The church condemned astrology as her-
esy, and as the practice of magicians and
charlatans. But astrology was strongly de-
fended by medieval authors such as Guido
Bonatti, the official astrologer of the city
of Florence, who set out his opinions in
the influential bookLiber Astronomicus.At
the mercy of a capricious natural world,
and the workings of fate that were often
difficult to explain, nobles and kings
sought the assistance of astrologers, who
promised to turn the wheel of fortune in
their favor.
In the fifteenth century, the printing
press began spreading astrology to a wider
audience. In addition to his Bibles, Jo-
hannes Gutenberg produced almanacs that
were widely imitated throughout Europe
and that served to make the dangerous,
unpredictable natural world a little more
predictable. Almanacs were calendars, with
a schedule of holy days and saints’ days,
advice on planting and harvesting, weather
forecasts, and prognostications of impor-
tant events. Worldly predictions made al-
manacs suspect to kings and their minis-
ters, however, and in many corners of
Europe it became a crime to publish as-
trological data and predictions. The church
remained adamantly opposed to astrology
as an occult practice, and in 1586 Pope
Sixtus VI condemned the practice in a fa-
mous papal bull (decree).
Nevertheless, nobles and royalty—and
many of the popes—were devoted believ-
ers in astrology; many of them employed
astrologers at their courts and made no
important decisions without taking into
consideration their advice. Important mat-
ters of state, and especially of war, never
were decided without the advice of as-
trologers, who claimed to eliminate chance
and misfortune with their complicated
charts and obscure language. Lucas Gauri-
cus was the official astrologer to Pope Leo
X and Pope Clement VII. Philipp Melanch-
thon was a renowned German astrologer
whose advice was often called upon.
Catherine de Médicis, a queen of France,
was devoted to astrology and employed
Michel de Notredame, or Nostradamus,
the most renowned astrologer of France.
Nostradamus published an important
work on astrology in 1555. At the re-
spected universities of Pavia and Bologna,
astrologers held professorships and vied
with astronomers for student followers.
Bologna, Milan, and Mantua were impor-
tant centers of astrological research during
the Italian Renaissance.
Traditional astrologers cast personal
horoscopes based on the position of the
planets at the time of one’s birth. Thereastrology