Katarche is an ancient Greek

Koine Greek

Koine Greek is the universal dialect of the Greek language spoken throughout post-Classical antiquity , developing from the Attic dialect, with admixture of elements especially from Ionic....

 word meaning a "beginning" or "inception."

One of the older applications of the term was within the context of religious rituals

Ancient Greek religion

Greek religion encompasses the collection of beliefs and rituals practiced in ancient Greece in the form of both popular public religion and cult practices. These different groups varied enough for it to be possible to speak of Greek religions or "cults" in the plural, though most of them shared...

 to refer to the moment when the sacrifice

Sacrifice

Sacrifice is the offering of food, objects or the lives of animals or people to God or the gods as an act of propitiation or worship.While sacrifice often implies ritual killing, the term offering can be used for bloodless sacrifices of cereal food or artifacts...

 was first offered, or when the beginning or inception of the sacrifice took place. (See Homer

Homer

In the Western classical tradition Homer , is the author of the Iliad and the Odyssey, and is revered as the greatest ancient Greek epic poet. These epics lie at the beginning of the Western canon of literature, and have had an enormous influence on the history of literature.When he lived is...

, Odyssey

Odyssey

The Odyssey is one of two major ancient Greek epic poems attributed to Homer. It is, in part, a sequel to the Iliad, the other work ascribed to Homer. The poem is fundamental to the modern Western canon, and is the second—the Iliad being the first—extant work of Western literature...

, Chapter III.)

The main application of the term "katarche" in the Hellenistic and Roman period was to the branch of astrology now called electional astrology

Electional astrology

Electional astrology, also known as event astrology, is a branch found in most traditions of astrology in which a practitioner decides the most appropriate time for an event based on the astrological auspiciousness of that time...

, or the art of choosing an auspicious time to begin a venture or an enterprise. Also included in this practice were techniques for analyzing an astrological chart drawn up for the beginning moment of an event that had already taken place, in order to foretell the likely success of a venture, or the timing of its development.

Recently, in the late 20th century, some astrologers began to extend the use of the word katarche to interrogations or horary astrology

Horary astrology

Horary astrology is an ancient branch of horoscopic astrology by which an astrologer attempts to answer a question by constructing a horoscope for the exact time at which the question was received and understood by the astrologer...

, where a chart is cast for the moment that a question is posed to an astrologer. According to this modern interpretation there is a fluid connection between the notions of electional and horary astrology. This view, which is primarily advocated by Geoffrey Cornelius, is that the origins of the concept and core meaning of the term katarche lie in the ritual, sacrificial and divinitory connotations of the term, and that the later application of the term in the Hellenistic and Roman periods strictly to elections and inceptions were a result of some sort of decay in the understanding of the term.