Vettius Valens

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Vettius Valens ( February 7, 120 ; † after June 184 ) was a Greek astronomer and astrologer of the 2nd century AD. He wrote the nine-volume work Anthologiae , which is considered a pioneering work with regard to astrological assignments of weekdays . It was written between 150 and 175 and is the oldest direct evidence of the introduction of the seven-day week based on the planet names .

background

In order to determine the respective planetary rulers over the hour , day, month and year, Vettius Valens developed the procedure of a horoscoped birth. As his own date of birth he named the first hour after sunset on Mechir 13th (February 7th) 120 in the fourth year of Hadrian's reign . As a further basis, Vettius Valens chose 1st Thoth as Sunday in the first year of Augustus ' reign , using the Egyptian calendar as a reference.

In this context, Vettius Valens mentions two further epochs for determining the annual regents. At the beginning of the year he took over the heliacal rise of Sirius . The explicit reference and naming of the underlying time periods confirms the assumptions that Egypt played an important role with regard to the seven-day planetary week.

Calculation of solar and planetary lengths

In Anthologiae I, 20 , Vettius Valens wrote rules of circulation based on his personal calculations. He determined the orbital lengths of the sun and the planets Jupiter , Mars , Saturn , Mercury and Venus . Vettius Valens defined the era of Augustus as the starting point and calculated the circulations since then in full years.

For the calculation for Venus, he used the eight-year synodic period, in which Venus is in conjunction five times through the 584-day intervals . The daily difference, which had passed since 1st Thoth, acted as the calculation scheme for Mercury.

literature

Text output
Secondary literature
  • Otto Neugebauer , Henry-Bartlett van Hoesen: Greek Horoscopes . American Philosophical Society, Philadelphia 1959.

Individual evidence

  1. ↑ On the date of death after June 184 AD see Stephan Heilen: 'Hadriani genitura' - The astrological fragments of Antigonus of Nikaia . Walter de Gruyter, Berlin 2015. p. 263. In Valens Anthologiae a birth horoscope for the year 132 AD and biographical events of the 52nd year of life are given as well as calculations for June 9th, 184 AD.

Web links

personal data
SURNAME Vettius Valens
ALTERNATIVE NAMES Valens, Vettius
BRIEF DESCRIPTION Greek astronomer and astrologer
DATE OF BIRTH February 7, 120
DATE OF DEATH 175