Hyleme

Hyleme, according to some schools of astrological and philosophical thought, refers to the essential point or factor in a nativity that is considered the vehicle of life. It is the part of the horoscope most vulnerable to attack or affliction and, therefore, the indicator of longevity and the potential for death. The determination of the hyleme varied between different astrological traditions, but it generally involved identifying a key planet or point representing vitality, such as the Sun, Moon, Ascendant, or Pars Fortuna (Part of Fortune).

In Hellenistic astrology, the hyleme was meticulously chosen by the astrologer based on several factors, including the sect of the native (whether the native was born during the day or night), the positions of the planets, and their relationships to the angles of the chart. The placement and condition of the hyleme, along with that of the alchocoden (the giver of years), were then carefully scrutinized to determine the length and quality of the native's life.

The concept of hyleme highlights the fatalistic aspects sometimes present in ancient astrological practices, where the stars were believed to dictate life's events, including its duration. While not universally accepted by all astrologers, the hyleme remains a significant term within the historical and theoretical framework of astrology. Its interpretation required significant astrological knowledge and was considered a complex and specialized technique. The concept is related to, but distinct from, that of critical degrees and fixed stars believed to have influence on fate.