You must have noticed this and wondered why the horoscope starts with Aries which is the sign of the natives between March and April and not the sign of the natives of January. There is a precise astrological motivation behind this choice.
The first observation from astrologers is that Aries is a fire sign. Fire is the dominant element of creation, it is the one that marked the beginning of everything.
When God created the world, the first thing he did was to separate the light from the darkness. God commanded, "Let there be light," and created the Sun, a fiery star.
The fire also marks a turning point in the Odyssey. Ulysses, who personifies the Sun, manages to get out of the dark and gloomy cave of Polyphemus by jumping on the back of a Ram. Since then the Sun began to be revered.
And again according to Heraclitus, the beginning and end of everything is sanctioned by fire. Fire gives life through the heat of the sun, and fire takes life by burning everything.
Earth is a living planet thanks to fire. According to genesis, the earth was born from fire and through the heat of fire it would expand, expanding it would become water, which in turn heated by fire would evaporate generating air.
The sun is the heavenly fire, because it sustains life as the soul sustains the body. Finally, the soul also has a fiery nature.
So, if the horoscope starts with a fire sign, the reasons are clear and multiple. But why Aries and not another fire sign?
The reason is that Aries is synonymous with renewal.
March 21 coincides with the spring equinox, the season in which we are witnessing a rebirth of nature.
March 21 is also the date that coincided with the New Year in antiquity, especially for the Greeks and Romans.
Our calendar with the institution of months starting on January 1 follows the establishment of the Gregorian calendar in the late 16th century. Astrology is a very ancient art.