The Origins of Astrology

Astrology, sometimes referred to as an astrological science, is the practice of interpreting how the positions and movements of celestial bodies—such as the Sun, Moon, planets, and stars—relate to events and patterns in human life.

The theoretical foundations of astrology trace back to ancient Greek philosophy from roughly 300 BCE to 300 CE, which held that celestial bodies, especially planets and constellations, exert a causal—or at least nonrandom—influence on earthly events. This outlook blended with the ancient Mesopotamian concept of celestial “omens.” Astrologers believed that the motions and configurations of certain celestial bodies were linked to the emergence and dissipation of the four elements on Earth: fire, air, water, and earth. The complexity of these correspondences mirrored the intricate nature of change in human affairs. Views on the role of deities varied. Some maintained that the universe operates entirely mechanically, denying both divine intervention and human free will. Others argued that astrology, unlike astronomy, can only indicate tendencies in how events may unfold—tendencies that can be altered by human or divine agency. Still others regarded the planets as powerful deities whose intentions could be swayed through prayer, and held that the heavens reveal divine will only to those versed in astrology. This perspective echoes that of ancient Mesopotamians, who primarily forecast impending fortunes and misfortunes for the royal court—manifesting as weather changes, diseases affecting people and crops, or impacts on major state affairs or the lives of the royal family. Yet they believed celestial omens did not determine the future; they signaled divine intent.

Astrology’s original aim was to predict an individual’s fate from the positions of the planets and the zodiac at the time of birth. It later developed into several branches: mundane astrology, which studies the relationship between major celestial events (such as eclipses or the vernal equinox) and human affairs; electional astrology, which selects auspicious times for action; and horary astrology, which answers specific questions based on the celestial conditions at the moment of inquiry.

Astrology grew out of the celestial-omen tradition of ancient Mesopotamia. During the Babylonian period from the 18th to the 16th century BCE, the first cuneiform texts cataloging celestial omens appeared. Between the 6th and 4th centuries BCE, this doctrine spread to Egypt, Greece, the Near East, and India, and it was later carried to Central Asia by Indian monks. From the 3rd century BCE onward, some practitioners began to model mathematically the correspondence between the macrocosm and the microcosm—the human body. They subdivided the zodiac into finer segments, holding that the influence of the five visible planets varied with their positions in these divisions. The effect of a given star or planet on a person depended on its segment and its relationships with other segments. The twelve zodiac signs were mapped to specific parts of the human body, suggesting that the ever-changing material world and human character are in some way related to the zodiac. Astrologers calculated planetary influences using the coordinates of the Sun, Moon, and five planets at a given moment, the positions of the zodiacal signs, and the complex geometric relationships among them. They then cast charts to correlate these factors with earthly events and draw astrological judgments. When results conflicted, astrologers reconciled them using the querent’s circumstances and their own experience. By the 1st century CE, these methods had become standardized.

Greek astrology also spread to India and Iran and became part of Islamic scholarly culture. After the 17th century, with the acceptance of the heliocentric model and the rise of modern science, astrology lost its scientific standing. Even so, the West has seen a modern resurgence, with some practitioners incorporating the outer planets discovered in modern times and attempting to establish statistical relationships between planetary positions and human life.