These early Synergy-relevant writings are thought to have appeared before the current era.

Uniting Yin and Yang (2nd Century BCE)

Archeologists discovered these document fragments in a Han dynasty tomb.

Tirumantiram by Thirumular

This ancient poem is sometimes misdated, but apparently dates from ~9th century CE at the earliest.

Phaedrus by Plato (360 BCE)

Phaedrus records a dialogue between Socrates and Phaedrus that addresses the challenge of using sexual desire wisely.

The Symposium by Plato (360 BCE)

The Symposium addresses how procreative urges tint perception of “love”, as well as the non-procreative use of desire.

Taharat Hamishpacha (“kosher sex”) (~400 BCE)

While its origins relate to ritual purity, this practice also promotes relationship harmony.

Iphegenia at Aulus by Euripides (405 BCE)

Playwright Euripides warns that desire can lead to obsession and disgrace…or to lifelong joy if used calmly.

The Way of Harmonizing Yin and Yang by Emperor Chuan Hsu (~1000 BCE)

Text offers spiritual guidance for sexual union, purportedly from “the ancient achieved ones”.

You can find other early writings in 1 CE – 400 CE.