beneficial or not by determining if the ruler of the part was a benefic. Likewise, a judg-
ment as to good or evil could be made in this way, again on the basis of the benefic or
malefic nature of the part’s ruler. The strength of the ruler of the part and its aspect (or
lack of same) to the significator could also yield helpful information. This is what
Guido Bonatti obscurely alludes to when he cites Albumasar in his discussion of the
parts in Liber Astronomiae.Lynn Thorndike, in The History of Magic and Experimental
Science,calls Bonatti “the most influential astrologer of the thirteenth century.” Bon-
atti’s work (Liber Astronomiae) was a major source for traditional medieval European
astrological practice.
In his “146 Considerations” (Tractatus V of Liber Astronomiae;translated into
English and published by Henry Coley in 1676, and recently republished by the
American Federation of Astrologers under the title Anima Astrologiae), Bonatti dis-
cusses another way the concept of the parts could be used to clarify murky testimony
in horary figures when the planetary indications are inscrutable. He suggests making
parts of those house rulers that related to the matter considered. This is what he advo-
cates in Considerations 144 and 146.
Jean Ganivet, in Amicus Medicorum(1508), provides us with an example of
the use of the parts in iatromedical diagnosis. He casts a horary figure for the dean of
Vienne, seeking to determine whether the dean would survive his current illness or
not. He concludes, after considering the Lights, the Part of the Killing Planet, the Part
of Death, the Part of Life and the Part of Fortune, all of which were adversely placed,
that the dean will fall into delirium in 24 hours and die within two days. He reports
that such was the case.
In natal figures, the parts were usually used to get a deeper understanding of
the native’s life. For instance, the Part of Fortune was called the lunar ascendant and
provided the medieval astrologer with information relating to the native’s inner moti-
vation (as opposed to outer drives imposed upon one by physical and worldly
demands). The Part of the Sun (Pars Solis, Pars Futurorum, Pars Spiritus, Pars Daemo-
nis) signifies, Bonatti tells us, in Libe Astonomiae,the soul and the body and their qual-
ity, as well as faith, prophecy, religion and the culture of God, secrets, cogitations,
intentions, hidden things, etc. It is found in a way different from that in which the
Part of Fortune is found: In diurnal figures, the distance from the Moon to the Sun is
projected from the ascendant; in nocturnal figures, the distance from the Sun to the
Moon is projected from the ascendant. Bonatti’s work catalogs the parts according to
the themes of the houses. His parts of the seventh house contains numerous parts
intended to reveal the marital fidelity of husband and wife, thus providing the
astrologer with material useful in synastry, although it is here that his medieval monk-
ish misogyny shines forth most glaringly.
The parts also had application in economic forecasting. Bonatti gives us an
involved (and largely accurate) technique for commodities forecasting! In addition,
the parts were used in mundane figures (ingresses; also known as Revolutions of Years
of the World).
The parts were used extensively by the Arabic astrologers, who greatly
increased their number. Bonatti, who relies on Arabic sources, lists 128 parts. Al-
THEASTROLOGYBOOK [41]
Arabic Parts