"Zen" is just the Japanese misreading of the Chinese characters for "Chan", the transliteration of the Sanskrit (Hindu) expression "dhyana", which means meditation. But that's only the end of meditation history which started, according to Matt Rossano (Did Meditation make uns Human? In :Cambridge Archeological Journal, Februar 2007) about 100.000 years ago, when homo sapiens joined hominid-people, who already lived for a long time around the world.
Most Hominids were a rather weak pray to each other and to hungry animals. But sometimes (according to Rossano) hominids, who stayed silently longer than necessary around their campfire were not attacked.
It took some 10.000 years until some homo sapiens too practiced silent sitting around the campfire to prevent animal attacks and cannibalism.
About 74,000 years ago with a tremendous bang Mount Toba on today's Sumatra literally exploded and blasted millions of tons of dust and stones into the Stratosphere.
It was the biggest volcanic eruption on earth in the last two million years. For years and years it was dark and continuously winter, a time like in ice age.
All forms of life on the Indian subcontinent were suffocated and buried under three to six meters of volcanic stones and dust.
The volcano killed about 70% of the world's hominid population. Modern humans, homo sapiens, survived outside Africa, only in Asia.

Mt.Toba -- How it happened
10,000 years later the human history of ancient India continued with survivors of the volcanic eruption, people from Africa, South- and Middle-Asia.
The newcomer to India developed and became its indigenous population, todays dravidians. During their long migration these homo sapiens practiced their protective behavior to stayed together after meals in "meditation". Homo sapiens with larger brains then other types of hominids not only remembered but sometimes learned to use the protective "sitting together" today called "meditation" .
After again 10.000 years the human population re-occupied India and south-east Asia. But about 42.000 years ago suddenly the protective magnetic cover of the planet was reduced to ca. 5% of it's normal strength (Laschamp-event). Deadly cosmic beams killed much life on earth. Many living beings on the planet dyed or even dyed out. Hunter gatherer hominids dyed out even the clever homo neanderthalensis. Only homo sapiens survived, because they still lived in caves.

Travelling Overseas
A genetic survey in South India discovered Dravidian people genetically close to indigenous Australians!
While East Asia and Europe became populated by humans who fled the droughts in central Asia, some migration from today`s Tibet added to the ancient Indian population.
Some Dravidian groups later may have migrated into the Indus civilization to learn about agriculture techniques and protective "meditation".
Like their cousins in Australia, the indigenous populations of India were displaced and marginalized by human groups of Aryan origin.
In Australia the takeover happened in the 18th century and the intruders came from northern Europe. In India it happened about 7 thousand years earlier and the intruders came from the Indus Valley.

History of India Timeline