Three Suns (eschatology)

The belief in Maitreya arose and has spread throughout China thanks to the translation of Buddhist scriptures from India starting in the 2nd century.

[7] Evidence of the concept of the three ages theory is found in the Yunji Qiqian (雲笈七籤), a text written in the early 11th century by Zhang Junfang (張君房 ) for his emperor.

[12] The earliest written evidence of this doctrine can be found in the Huangji jieguo baojuan (皇极结果宝卷), published in 1430.

[15] The three sun period theory is also found “The Treasure Scroll of the Emperor's Supreme Golden Elixir, the Nine Lotuses and the Correct Belief in the Truth, and the Return to Heaven” (皇極金丹九蓮正信歸真還鄉寶卷), a scripture that was used by Green Lotus sect (青蓮教) as the basis of the sect's doctrine.

[17] The doctrine of the Three Ages is discussed in Neo-Confucian and New Confucian teachings, the Gongyang Commentary and the Datong shu of Kang Youwei.

[21] In the third age humankind attains Datong, ren is fully realised as people transcend their selfishness and become one with "all under Heaven".