Huangdi's Gregorian calendar

One refers to the historical period, that is, the Three Emperors era (BC? Years ~ 3077 BC).

Secondly, they are three outstanding tribal leaders in ancient legends of China, and later generations are honored as emperors. In the pre-Qin period, Huang San's divine attribute was higher than human attribute, and Huang San had the nature of emperor, and later generations were more recorded as the ancestors of human beings.

Emperor, Emperor, Tai Huang; Historical records from Qin Shihuang

Emperor, Emperor, Ren Huang; Excerpted from "Supplement to Historical Records and Huang San's Biography"

Suirenshi, Fuxi, Shennong; From The Great Biography of Shangshu

Fuxi, Nuwa, Shennong; Excerpted from "Customs Yi Tong Ba Huang Chapter"

Fuxi, Shennong, Zhu Rong; From White Tiger Hall

Fuxi, Shennong and Gonggong; From A Mirror