(BAZI)Four Pillars of Destiny was dated back to Han Dynasty when recording was put in place for future references. During the time of Tang Dynasty, Lǐ Xū- Zhōng (Chinese:李虛中) use this concept and put into a person’s birth year, month and date to predict one’s person personality and future endeavour, it is called as
Three Pillars of destiny in English, after then this theory become more and more popular as time goes by.
During Song Dynasty, Xú Zi Píng (Chinese:徐子平), who reformed Lǐ Xū- Zhōng’s
(BAZI)The Three Pillars of destiny, added the
birth time as the forth pillar, which means added another 2 sexagenary cycle characters to person’s fate pillars, from
six characters into
eight characters, the forecast accuracy was much higher and became more useful. Therefore, people regarded Xú Zi Píng that he laid a solid foundation of Four Pillars of Destiny.
Days, hours, months, and years are all assigned one of the Ten Celestial Stems and one of the twelve Earthly Branches in the sexagenary cycle. A person’s fortune is determined by looking up the branch and stem characters for each of these four parts of their birth time.
For more information, please visit here https://en.wikipedia.org/wiki/Four_Pillars_of_Destiny