Placidus de Titis (or Titus) (1603–1668)
Italian astrologer, mathematician, and Roman Catholic
monk, born at Perugia, Italy, into a prominent noble family.
Little is known of his early life prior to his joining the Olivetian
order around 1624 at age 21. He later became a reader of
mathematics and physics at the University of Padua and then
in 1657 was appointed professor of mathematics at the Milanese
University in Pavia. He remained at Pavia for the rest of
his life.
In Placidus’s lifetime, astrology was still the proper concern
of scholars and churchmen, and Placidus served as astrologer
to a number of prominent political leaders, including Leopold
William (1614–62), the archduke of Austria. In his studies he
focused upon Claudius Ptolemy’s ancient astrological work the
Tetrabiblos, and in it he believed he had discerned Ptolemy’s lost
method of ‘‘dividing houses.’’ (In reading an astrology chart,
one must not only divide the chart into the 12 astrological signs
but also rotate the chart to account for the rotation of the earth
during a 24-hour period. Astrological houses serve as a second
division system that (among other functions) facilitates that rotation.
Placidus published his findings in two volumes in 1650
and 1657.
The work of Placidus had little immediate impact on astrology,
which was entering a period of decline even as he was writing.
At the end of the eighteenth century, however, as the revival
of astrology began in England, Manoah Sibley translated
some writings of Placidus into English, and a second translation,
by John Cooper, was published in 1814. R. C. Smith, better
known under his pen name, Raphael, used Sibley’s translation
in his annual Raphael’s Ephemeris, the most popular
ephemeris for the next century. (An ephemeris provides the
daily charts of the planets and is used by astrologers to quickly
prepare a horoscope chart.) Raphael’s Ephemeris is still published
and is used by many astrologers in Great Britain.
Through Raphael the Placidian system became the dominant
system in astrolgy today.
Baugnet, Michael. Introduction to Primum Mobile. . . . by
Placidus de Titis. Translated by John Cooper. London Davis
and Dickson, 1814.
Encyclopedia of Occultism & Parapsychology • 5th Ed. Placidus de Titis
Brau, Jean-Louis, Helen Weaver, and Allan Edwards, eds.
Larousse Encyclopedia of Astrology. New York New American Library,
Holden, James H., and Robert A. Hughes. Astrological Pioneers
of America. Tempe, Ariz. American Federation of Astrologers,
Lewis, James L. The Astrology Encyclopedia. Detroit Gale Research,
Placidus de Titus. Astronomy and Elementary Philosophy.
Translated by Manoah Sibley. London W. Justins, 1789.
———. A Collection of Thirty Remarkable Nativities. Translated
by Manoah Sibley. London W. Justins, 1789.