Tetrabiblos - Literally, "four
books." (Greek tetra means "four," biblos
is "book"). Ptolemy's work on Astrology. While it may
seem strange that someone who wrote such excellent
scientific books should write on Astrology, Ptolemy saw it
differently. He claimed that the Almagest allowed one to
find the positions of the heavenly bodies, while he saw
his Astrology book as a companion work describing the
effects of the heavenly bodies on people's lives.
His treatise on Astrology, Tetrabiblos, was the most popular
astrological work of antiquity and also enjoyed great
influence in the Islamic world and the medieval Latin West.
Tetrabiblos is an extensive piece of writing on the ancient
principles of Horoscopic Astrology. The great popularity of
the Tetrabiblos might be attributed to its nature as an
exposition of the art of Astrology and as a compendium of
astrological lore, rather than as a manual. It speaks in
general terms, avoiding illustrations and details of
practice. (Ptolemy was concerned to defend Astrology by
defining its limits and compiling astronomical data that he
believed was reliable).
Much of the content of Tetrabiblos may well have been
collected from earlier sources; Ptolemy's achievement was to
order his material in a systematic way, showing how the subject
could, in his view, be rationalized. His astrological outlook
was quite practical: he thought that Astrology was conjectural,
because of the many variable factors to be taken into account.
Therefore, he saw Astrology as something to be used in life,
but not to be relied on entirely.
Tetrabiblos was long thought to be a complete survey of
Greek Astrology. Recent research suggests this not to be the
case, but Ptolemy’s work remains the foundation of western
Astrology. In particular, his persuasive use of the Tropical
Zodiac, rather than the Sidereal, changed western Astrology
various technical terms and supplies other
information needed by the astrologer. e.g.
Chapters 9, 10 and 11 detail the influence of
fixed stars in various constellations.
- Is the
astrology of nations and their rulers.
to Natal Astrology, explains Ptolemy’s method of
rectifying the Ascendant. Chapter 10 gives a
method for determining life expectancy.
with fortunes of wealth & rank, as well as
employment, marriage, children, death, etc.
Also included are extracts from Ptolemy's
Almagest (a compendium of Greek astronomy), as well as
"Ptolemy’s Centiloquy," a list of aphorisms. Many of the 100
deal with Horary Astrology. They have been studied by
astrologers for centuries.
Tetrabiblos: Gardner, (1911), lists
four English translations of Tetrabiblos:
- The first was by John Walley, 1701.
- The second was Walley’s translation, edited by Sibley
and Brown, 1786, which is said to be worthless.
- The third, by James Wilson (author of the famous
Dictionary of Astrology), was published in 1820.
- The fourth (this one, by far the best), was by J.M.
- Also, a fifth translation was made in 1940 by F.E.
Of these several translators, only Ashmand could claim to
be both a Greek and Latin scholar as well as an experienced
astrologer. Every serious astrologer, from the 3rd century
to the present, has studied the Tetrabiblos. With the
current revival of traditional Astrology, it remains
essential reading. (The Metaphysical Society
pleased to offer Ashmand’s translation of Tetrabiblos
in four e-Books to students of Astrology).
Notable Works Ascribed to
- Almagest: A
treatise in thirteen books. Although the work
is now almost always known as the Almagest that was not its
original name. Its original Greek title translates as The
Mathematical Compilation or Syntaxis Mathematica, but this
title was soon replaced by another Greek title which means
The Greatest Compilation. This was translated into Arabic
as "al-majisti" and from this the title Almagest was given
to the work when it was translated from Arabic to Latin.
The Almagest is the earliest of Ptolemy's works and gives,
in detail, the mathematical theory of the motions of
The Sun, The Moon, and The Planets. Ptolemy made his most
original contribution by presenting details for the
motions of each of the planets. From its conception in
the second century up to the late Renaissance, this work
determined astronomy as a science. During this time the
Almagest was not only a work on astronomy; the subject
of astronomy itself was defined by what is described in
the Almagest. As an instructive work, the Almagest is a
masterpiece of clarity and method, superior to any
ancient scientific textbook and with few peers from any
period. But it is much more than that. Far from being a
mere "systemization" of earlier Greek astronomy, as it
is sometimes described, it is in many respects an
original work. Ptolemy's "Almagest" shares with Euclid's
"Elements" the glory of being the scientific text
longest in use. From its conception in the second
century up to the late Renaissance, this work determined
astronomy as a science. During this time the "Almagest"
was not only a work on astronomy; the subject was
defined as what is described in the "Almagest". Ptolemy
describes himself very clearly what he is attempting to
do in writing the work;
"We shall try to note down
everything which we think we have discovered up to the
present time; we shall do this as concisely as possible and
in a manner which can be followed by those who have already
made some progress in the field. For the sake of
completeness in our treatment we shall set out everything
useful for the theory of the heavens in the proper order,
but to avoid undue length we shall merely recount what has
been adequately established by the ancients. However, those
topics which have not been dealt with by our predecessors
at all, or not as usefully as they might have been, will be
discussed at length to the best of our
The Almagest was not superseded until a century after
Copernicus presented his heliocentric theory in the De
revolutionibus of 1543.
- Geographia: In eight books,
Ptolemy attempts to map the known world giving coordinates
of the major places in terms of latitude and longitude. It
includes a catalogue of places with latitude and longitude,
several maps, including a map of the
- Tetrabiblos: Literally, "four
books." Ptolemy also wrote a work on Astrology. While it
may seem strange that someone who wrote such excellent
scientific books should write on Astrology, Ptolemy saw it
differently. He claimed that the Almagest allows one to
find the positions of the heavenly bodies, while he saw his
Astrology book as a companion work describing the effects
of the heavenly bodies on people's lives.
- De Analemmate
(Analemma): Methods of finding the angles
need to construct a sundial which involves the projection
of points on the celestial sphere.
- Planisphaerium: Dealing with
stereographic projection of the celestial sphere onto a
- Optics: In
five books. In Optics, Ptolemy studies colour, reflection,
refraction, and mirrors of various shapes. Noted for the
establishment of theory by experiment, frequently by
constructing special apparatus. Whether the subject matter
is largely derived or original, "The Optics" is an
impressive example of the development of a mathematical
science with due regard to physical data.
- On the Apparitions of the
Fixed Stars and a Collection of
- On the Planetary
- Table of
Reigns: a chronological table of
- On Music: in
Centiloquium: a collection of astrological
- Ready (astronomical)
- Scheme and Manipulation of
the Ready Tables
- The Theory of Knowledge and
The Soul a short treatise
- Maps -
including a map of The World (Description: The World,
by Claudius Ptolemy, Cartographer and Engrave by Johannes
As a final comment we quote the epigram
which is accepted by many scholars to have been written by
Ptolemy himself, and it appears in Book 1 of
"Well do I
know that I am mortal, a creature of one day. But if my mind
follows the winding paths of the stars
Then my feet no longer rest on earth, but standing by Zeus
himself I take my fill of ambrosia, the divine