One day, in ancient India, the Buddha was giving a teaching to his followers. On this day however, instead of a verbal teaching,
he simply held up a flower. One of his disciples, Mahakasyapa, smiled. The Buddha said:
“Today, I gave a silent teaching and Mahakasyapa alone understood it.”
This was the birth of Zen.
Since that time, the Buddha’s message has been transmitted from person to person right up to today’s modern Zen masters.
From: Zen Buddhism