The planetary hours have been known among astrologers since ancient times. They were used in horoscopes and necromancy. And the papal bull of 1279 and the “Bibliotheca secreta” of John Trevisa (1340) mention the planetary hours. The first almanac of planetary hours was created in 1505 by the Swiss astrologer and physician Purbach. The almanac was based on the planetary hours’ research of the Arabian astrologer Abul-Wafā. The almanac included the planetary hours, which were evaluated as favorable or unfavorable. The planetary hours and favorable and unfavorable hours were specified in the work on magic and astrology by J.C. Vigelius “The Physician’s and Astrologer’s Treasure” (1538), and in the work of Ficinus “De divinatione astrorum” (1535). The system of planetary hours was used in the horoscopes by W. Lilly in “Christian Astrology” (London, 1647).
The planetary hours were known in the Arab tradition as an-nawātil (sing. an-nātīl), that is “the measures,” although such an Arabic word has been hardly found in the Arabic literary sources. It is remarkable that the word an-nawātil is used in the description of the planetary hour system in some Arabic sources: “While other hours are indeterminate and do not move, these hours move and the hours are the measures for the stars.” (V. Shklovskii. Ancient Astrology. Moscow, 1995. P. 101).
Over 100 texts with the description of the planetary hours were found in the West Asian and North African scholarship of medieval astrology. Some of them are “The Book of the Thirty Hours” and “The Book of the Sixteen Hours” by the Persian astrologer Haly Abenragel (13. c.), “The Book of the Balance of the Hours” by the Egyptian astrologer Ibn al-Mummāri (14. c.), and “The Book of the Balance of the Hours” by the Arab astrologer Abū Maʿshar (9. c.).
The planetary hours system was adopted in the horoscope compilation “The Book of the Balance of the Hours”.
The history of the planetary hours system is connected with the history of the ancient Babylonian astrology, and Zoroastrian astrology, which preceded the Babylonian one. The latter had three planetary hours: AM (that is, morning), noon, and PM (that is, evening) corresponding to the rising times of the planets Venus, Jupiter, and Saturn. These were called the “Three Planets” or the “Three Lords”. The Three Planets represented the past, the present, and the future. In the Babylonian astrology, Venus was the morning star, and Jupiter was the planet of the day. Saturn was the evening star, and would later become associated with the night in the astrology of the Hellenistic period.
The Babylonians also developed a system of astrological houses. The exact time when the planets passed through the houses in the natal chart was of significance. It was believed that the planets in the houses were responsible for life events. The system of planetary hours was used in the Babylonian astrology along with the 12 houses system.
Some researchers believe that the system of planetary hours was developed independently of the Babylonian astrology by Ancient Egyptian astrologers. According to this hypothesis, the system of planetary hours was already known in Ancient Egypt. In any way, it was the ancient Egyptian astrology that influenced the development of the Babylonian and the Greco-Roman astrology. The Egyptian astrology had a system of 36 decans, which were divided into three groups of 12 hours each. The decans represented the positions of fixed stars. As a result, the ancient Egyptian astrologers believed that the sky was divided into 36 sectors, which were associated with the 36 decans. The decans were believed to influence human life. The decans were considered favorable when they rose at the ascendant and unfavorable when they appeared in the lower sky or in the opposite natal chart sector.
The main source of our knowledge about the influence of the planets on the people is the work of the Greek astrologer Valens. He described the influence of the planets in his work “Mantissa”.
The work by Ptolemy “Tetrabiblos” was widely known in Arab and medieval Europe. Ptolemy’s work described the influence of the planets on the people. In his work, Ptolemy described the effects of the planets as follows:
It should be noted that the order of the planets in the table is different from the modern one. In ancient astronomy, the order of the planets was different. First, the Moon and Sun were the planets. Then, they were replaced by Venus, Mercury, Mars, Jupiter, and Saturn. The Ptolemaic table had been developed in the Hellenistic period, and its authors did not know about the order of the planets in the modern sense.
Another horoscope compilation, which is known as Almagest, was written by the Greek astronomer Claudius Ptolemaeus. It includes a list of planetary hours, which are used in the horoscopes.
The planetary hours system was used in ancient horoscopes. For example, it was used by the Babylonian astrologer-priest Marduk in the horoscope compilation “The Book of the Balance of the Hours” during the first century of the common era.
The planetary hours system was widely used in horoscopes. The Babylonian astrologer-priest Marduk mentioned the planetary hours in his horoscope compilation “The Book of the Balance of the Hours”.
The Roman astrologer Vettius Valens used the planetary hours in his work “Mantissa”.
The Syrian astrologer Paulus Alexandrinus used the planetary hours in his work “The Canons”.
The Syrian astrologer-priest Johannes Kamateros used the planetary hours in his work “The Canons”.
The planetary hours were used in the horoscopes and necromancy in medieval Europe. For example, the horoscope compilation “The Book of the Thirty Hours” has been written by the Swiss astrologer and physician Purbach in 1505. This horoscope compilation has been considered the most important horoscope compilation in medieval Europe for the period. R. Asread “The Book of the Thirty Hours” (London, 1909) summarizes the results of the studies of this horoscope compilation.
The horoscope compilation “Vigiliae Christianae” was written by the German astrologer Henricus Cornelius Agrippa in 1520. This horoscope compilation includes the planetary hours.
The planetary hours were used in the horoscopes by the German astrologer and astronomer Reinhold. He used the planetary hours in the horoscope compilation “Variae observationes” in 1550.
The planetary hours were used in the horoscopes by the German Johannes Stöffler. He wrote the horoscope compilation “De Astronomia” in 1552.
The planetary hours were used in a horoscope by the English astrologer William Lilly. He wrote a horoscope compilation “Christian Astrology” in London in 1647.
The planetary hours system is mentioned in medieval necrology. There are necrologies of the astrologer-priest Johann Stöffler and the necrologies of the German astrologer Michael Maier from the 16th century. These necrologies mention the planetary hours.
The planetary hours system was used in the horoscopes by the French astrologer Jacques Firmicus Maternus. He wrote a horoscope compilation “Mathesis” (1540).