A timeline

 Here’s a simple historical timeline of Non-duality (Advaita / non-dual insight) from earliest roots to modern teachings:

1. Early Vedic hints (1500–800 BCE)

• Non-dual ideas begin as unity behind nature
• Example: “Truth is one, sages call it many” — Rig Veda
• Still mostly cosmic unity, not full Advaita yet

2. Upanishadic non-duality (800–300 BCE) — Birth of Advaita

Clear statements of Self = Absolute Reality

Key texts:

• Chandogya Upanishad — “Tat Tvam Asi” (You are That)
• Brihadaranyaka Upanishad — “Aham Brahmasmi”
• Mandukya Upanishad — Pure consciousness is all

This is the first full non-dual philosophy.

3. Classical synthesis (200 BCE – 200 CE)

Non-duality mixed with yoga and action

• Bhagavad Gita
  Teaches:
• act in world
• but Self is untouched
• unity behind all beings

Not pure Advaita, but proto-Advaita.

4. First pure Advaita philosopher (500–600 CE)

• Gaudapada
• Wrote Mandukya Karika

Radical claims:

• World is appearance
• No creation actually happened
• Only consciousness exists

This is earliest strict non-duality.

5. Systematized Advaita (788–820 CE)

• Adi Shankaracharya

He:

• organized Advaita
• wrote commentaries
• debated dualist schools

Core idea:

• Brahman alone is real
• world is appearance
• Self = Brahman

This becomes classical Advaita Vedanta.

6. Post-Shankara Advaita teachers (800–1700)

Important names:

• Sureshvara
• Vidyaranya
• Madhusudana Saraswati

They refined:

• illusion theory
• witness consciousness
• non-doership

7. Direct experience emphasis (1800–1900)

Non-duality becomes experiential

• Ramakrishna
• Ramana Maharshi

Ramana simplified Advaita to:

• “Who am I?” inquiry
• no-thought awareness
• Self alone exists

8. Modern Neo-Advaita (1900–present)

Non-duality stripped to essence

Teachers:

• Nisargadatta Maharaj
• Papaji
• Rupert Spira

Message:

• You are already awareness
• No path needed
• Nothing to attain

One-line evolution

• Vedas → unity of cosmos
• Upanishads → Self = Absolute
• Gita → act without ego
• Gaudapada → only consciousness
• Shankara → full Advaita system
• Ramana → direct self-inquiry
• Modern teachers → immediate non-duality

If you want, I can also show:

•  Buddhist non-duality timeline
•  Zen no-mind timeline
•  Comparison: Advaita vs Buddhism
• Or:  evolution of “no-thought” idea