History of astrology

is a belief in a relation between celestial observations and terrestrial events. People made conscious attempts to measure, record, and predict seasonal changes by reference to astronomical cycles. Early evidence of such practices appears as markings on bones and cave walls, which show that the lunar cycle was being noted as early as 25,000 years ago; the first step towards recording the Moon's influence upon tides and rivers, and towards organizing a communal calendar. With the Neolithic Revolution new needs were also being met by the increasing knowledge of constellations, whose appearances in the night-time sky change with the seasons, thus allowing the rising of particular star-groups to herald annual floods or seasonal activities. By the 3rd millennium BCE, widespread civilisations had developed sophisticated understanding of celestial cycles, and are believed to have consciously oriented their temples to create alignment with the heliacal risings of the stars.
There is scattered evidence to suggest that the oldest known astrological references are copies of texts made during this period, particularly in Mesopotamia. Two, from the Venus tablet of Ammisaduqa are reported to have been made during the reign of king Sargon of Akkad. Another, showing an early use of electional astrology, is ascribed to the reign of the Sumerian ruler Gudea of Lagash. However, there is controversy over whether they were genuinely recorded at the time or merely ascribed to ancient rulers by posterity. The oldest undisputed evidence of the use of astrology as an integrated system of knowledge is attributed to records that emerge from the first dynasty of Mesopotamia.
Among West Eurasian peoples, the earliest evidence for astrology dates from the 3rd millennium BC, with roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. Until the 17th century, astrology was considered a scholarly tradition, and it helped drive the development of astronomy. It was commonly accepted in political and cultural circles, and some of its concepts were used in other traditional studies, such as alchemy, meteorology and medicine. By the end of the 17th century, emerging scientific concepts in astronomy, such as heliocentrism, undermined the theoretical basis of astrology, which subsequently lost its academic standing and became regarded as a pseudoscience. Empirical scientific investigation has shown that predictions based on these systems are not accurate.
In the 20th century, astrology gained broader consumer popularity through the influence of regular mass media products, such as newspaper horoscopes.

Babylonian astrology

Babylonian astrology is the earliest recorded organized system of astrology, arising in the 2nd millennium BC. There is speculation that astrology of some form appeared in the Sumerian period in the 3rd millennium BC, but the isolated references to ancient celestial omens dated to this period are not considered sufficient evidence to demonstrate an integrated theory of astrology. The history of scholarly celestial divination is therefore generally reported to begin with late Old Babylonian texts, continuing through the Middle Babylonian and Middle Assyrian periods.
By the 16th century BC the extensive employment of omen-based astrology can be evidenced in the compilation of a comprehensive reference work known as Enuma Anu Enlil. Its contents consisted of 70 cuneiform tablets comprising 7,000 celestial omens. Texts from this time also refer to an oral tradition – the origin and content of which can only be speculated upon. At this time Babylonian astrology was solely mundane, concerned with the prediction of weather and political matters, and prior to the 7th century BC the practitioners' understanding of astronomy was fairly rudimentary. Astrological symbols likely represented seasonal tasks, and were used as a yearly almanac of listed activities to remind a community to do things appropriate to the season or weather. By the 4th century, their mathematical methods had progressed enough to calculate future planetary positions with reasonable accuracy, at which point extensive ephemerides began to appear.
Babylonian astrology developed within the context of divination. A collection of 32 tablets with inscribed liver models, dating from about 1875 BC, are the oldest known detailed texts of Babylonian divination, and these demonstrate the same interpretational format as that employed in celestial omen analysis. Blemishes and marks found on the liver of the sacrificial animal were interpreted as symbolic signs which presented messages from the gods to the king.
The gods were also believed to present themselves in the celestial images of the planets or stars with whom they were associated. Evil celestial omens attached to any particular planet were therefore seen as indications of dissatisfaction or disturbance of the god that planet represented. Such indications were met with attempts to appease the god and find manageable ways by which the god's expression could be realised without significant harm to the king and his nation. An astronomical report to the king Esarhaddon concerning a lunar eclipse of January 673 BC shows how the ritualistic use of substitute kings, or substitute events, combined an unquestioning belief in magic and omens with a purely mechanical view that the astrological event must have some kind of correlate within the natural world:
Ulla Koch-Westenholz, in her 1995 book Mesopotamian Astrology, argues that this ambivalence between a theistic and mechanic worldview defines the Babylonian concept of celestial divination as one which, despite its heavy reliance on magic, remains free of implications of targeted punishment with the purpose of revenge, and so "shares some of the defining traits of modern science: it is objective and value-free, it operates according to known rules, and its data are considered universally valid and can be looked up in written tabulations". Koch-Westenholz also establishes the most important distinction between ancient Babylonian astrology and other divinatory disciplines as being that the former was originally exclusively concerned with mundane astrology, being geographically oriented and specifically applied to countries, cities and nations, and almost wholly concerned with the welfare of the state and the king as the governing head of the nation. Mundane astrology is therefore known to be one of the oldest branches of astrology. It was only with the gradual emergence of horoscopic astrology, from the 6th century BC, that astrology developed the techniques and practice of natal astrology.

Hellenistic Egypt

In 525 BC Egypt was conquered by the Persians so there is likely to have been some Mesopotamian influence on Egyptian astrology. Arguing in favour of this, historian Tamsyn Barton gives an example of what appears to be Mesopotamian influence on the Egyptian zodiac, which shared two signs – the Balance and the Scorpion, as evidenced in the Dendera Zodiac.
After the occupation by Alexander the Great in 332 BC, Egypt came under Hellenistic rule and influence. The city of Alexandria was founded by Alexander after the conquest and during the 3rd and 2nd centuries BC, the Ptolemaic scholars of Alexandria were prolific writers. It was in Ptolemaic Alexandria that Babylonian astrology was mixed with the Egyptian tradition of Decanic astrology to create Horoscopic astrology. This contained the Babylonian zodiac with its system of planetary exaltations, the triplicities of the signs and the importance of eclipses. Along with this it incorporated the Egyptian concept of dividing the zodiac into thirty-six decans of ten degrees each, with an emphasis on the rising decan, the Greek system of planetary Gods, sign rulership and four elements.
The decans were a system of time measurement according to the constellations. They were led by the constellation Sothis or Sirius. The risings of the decans in the night were used to divide the night into 'hours'. The rising of a constellation just before sunrise was considered the last hour of the night. Over the course of the year, each constellation rose just before sunrise for ten days. When they became part of the astrology of the Hellenistic Age, each decan was associated with ten degrees of the zodiac. Texts from the 2nd century BC list predictions relating to the positions of planets in zodiac signs at the time of the rising of certain decans, particularly Sothis. The earliest Zodiac found in Egypt dates to the 1st century BC, the Dendera Zodiac.
Particularly important in the development of horoscopic astrology was the Greco-Roman astrologer and astronomer Ptolemy, who lived in Alexandria during Roman Egypt. Ptolemy's work the Tetrabiblos laid the basis of the Western astrological tradition, and as a source of later reference is said to have "enjoyed almost the authority of a Bible among the astrological writers of a thousand years or more". It was one of the first astrological texts to be circulated in Medieval Europe after being translated from Arabic into Latin by Plato of Tivoli in Spain, 1138.
According to Firmicus Maternus, the system of horoscopic astrology was given early on to an Egyptian pharaoh named Nechepso and his priest Petosiris. The Hermetic texts were also put together during this period and Clement of Alexandria, writing in the Roman era, demonstrates the degree to which astrologers were expected to have knowledge of the texts in his description of Egyptian sacred rites:

This is principally shown by their sacred ceremonial. For first advances the Singer, bearing some one of the symbols of music. For they say that he must learn two of the books of Hermes, the one of which contains the hymns of the gods, the second the regulations for the king's life. And after the Singer advances the Astrologer, with a horologe in his hand, and a palm, the symbols of astrology. He must have the astrological books of Hermes, which are four in number, always in his mouth.